Root 27 is a little more than root 25 which equals 5. Similarly, root 50 is a little more than root 49 which equals 7. So the answer is near 5/7. Answer b) is the only answer less than 1.
@robertloveless49389 ай бұрын
Quit being logical. I was taught (MANY years ago) to 1st eliminate the impossible. Coincidentally, that's whaf Sherlock Holmes said to do.
@thebasisti24829 ай бұрын
Yeah
@tuncayvsran31169 ай бұрын
B
@Alo-n7l8 ай бұрын
27
@Ghredle8 ай бұрын
Exactly my first aproach
@hraydetective8 ай бұрын
As a 74 year old former English major who had a career in IT I didn't need the coaching on test-taking, but the explanation on how to derive the answer algebraicly was worth the viewing.
@billh59238 ай бұрын
I fairly quickly did it in my head. Can't believe it took a 20-minute video to explain this simple problem.
@richardhole84297 ай бұрын
Note that this view has been seen by 179K people. How many on your channel?😢
@natashabacevic75997 ай бұрын
Me too, needed a minute in my head. Ridiculous
@nickfraser45992 ай бұрын
Not everybody is as facile as ye and me! The video is really for them as is not. But if they practice enough they will become so. Cheers!
@PaulEEish9 ай бұрын
I'm a tail-end baby boomer/gen X and was always a B+ or A- student in middle and high school and had to work hard at math. I am convinced that had I had a tutor like you (and YT) back then, I would have aced my math courses consistently. Nevertheless, because it's never too late to learn, I'm relearning basic math skills. Why, some might ask? It's because it gives me great joy to master what I know I can, reinforces what I already know, and keeps my mind sharp.
@YAWTon8 ай бұрын
The result is less than 1. This rules out a, c, and d. So the answer is b. To evaluate multiply by sqrt(2). This leads to sqrt(54)/10, which is the same as 3×sqrt(6)/10. The only thing that is difficult is how to make a 20 minutes clip out of a trivial problem...
@starblue35984 ай бұрын
I passed Algebra 2 in high school by guessing and eliminating wrong answers on multiple choice tests. ( teacher was too lazy to actually look at your work). Now I watch your channel to understand what I never did. (73 years old).
@geneloscowski30708 ай бұрын
I've been teaching advance math for 42 years. I've never seen such a complex solution to a simple problem!!!
@dough95128 ай бұрын
Complex?? Do you actually mean "time-wasting"?
@johnshaw67023 ай бұрын
I'm curious. What method you would use to prove that (b) was the correct answer? Although it is simple to assume (b) is correct, through logic, as he mentioned in the lesson, but in real life you don't have multiple choices given to you.
@davesutherland18642 ай бұрын
I agree. Lots of people have posted correct solutions that you can read in 30s. Even if you have to think about what they write a bit it should still take less than a minute to follow the logic.
@Kualinar8 ай бұрын
I start with a quick approximation. ✓27 is a bit larger than 5 (✓25), and ✓50 slightly larger than 7 (✓49). So, the result must be less than 1. The ONLY proposed answer that is less than 1 is (3✓6)/10, or about 0.735, (B). Many years ago, I solved a LOT of similar problems in my math classes. Thanks for the refresh.
@philipkudrna56438 ай бұрын
Sqrt(27) is 3*sqrt(3). Sqrt(50) is 5*sqrt(2). If we rationalize the denominator by multiplying with sqrt(2) we get 3*sqrt(2*3)/ (5*2) or 3*sqrt(6)/10 or answer b)
@keithclancy15379 ай бұрын
I don't think I ever had a Math teacher give multiple choices with only one possible answer. The numerator is smaller than the denominator therefore the answer is less than 1 only one choice has any possibility of being less than 1.
@robertloveless49389 ай бұрын
You'd be surprised how little common sense is emphasized in school anymore.
@jeffreyfoster84138 ай бұрын
The problem I have with multiple choice tests is life isn’t multiple choice. They just made it easier for teachers to grade.
@zembalu9 ай бұрын
Since this is a multiple choice question, it is trivial, because the result must be less than 1.
@cosimo77709 ай бұрын
Mental arithmetic in 2 seconds shows it is (b), because only (b) is less than 1. Maths teachers should teach insight, not absurd mechanical rules.
@gordonspond7 ай бұрын
Agree
@highpath47764 ай бұрын
@@gordonspond but if all answers were
@johnshaw67023 ай бұрын
OK. e) None of the above. Now are you as sure of the answer? The rules give you the base from which to build understanding. Understanding leads to insight. This is a video that teaches mathematics. He explained how you determine that the answer of (b) is the correct answer, but that is actually an assumption.
@Kyravexa9 ай бұрын
Took your way at first, got stuck at 11:22, then decided to take another step and expanding (hope that is the correct english word) Root27/Root50 by Root2 and got Root54/Root100 = Root54/10 = Root(9*6)/10 = 3*Root6/10, means b) is the correct solution
@nickfraser45998 ай бұрын
Take the squares out of each you end up with 3✓3 / 5✓2. Now multiply by ✓2/✓2 ( since that is one and you can get multiply anything by one and get away with it! ) and you end up with 3✓2✓3 / (5 *2) or 3✓6/10
@mata27238 ай бұрын
yes, the video explanations is so long for just this....
@ianwilson97162 ай бұрын
I appreciate the way he looks at possible misunderstandings then explains the various options, which leads to a deeper understanding
@troglokev8 ай бұрын
So that’s 3 root3/5 root 2. Multiply top and bottom by root 2 to get 3 root6/10. b. Not sure why this takes 20 minutes.
@b213videoz9 ай бұрын
Thanks to this American I can now solve these kind of problems (a few months ago I couldn't)
@timmiddleton92277 ай бұрын
Dude, thanks anyway, but I died & was buried waiting for you to solve it. Geez, we are mortal after all.
@Shay-q8u7 ай бұрын
enjoy being at best a d student then.
@johnshaw67023 ай бұрын
Thanks. I came up with the presumption that the answer was (b) because √27 < √50, and would have chosen that on a timed test. At 64 I rarely do math and got as far as (9 x √3)/(5 x √2) in my head, but decided that was enough mental excercise without writing it down. So I watched the video instead. You did a good job of expainig how to prove that the presumption was correct. I said "presumption" above because of the fact that without proof you are only assuming that one of the given choices is correct. In other words, you are making an educated guess, because the answer must be less than 1.
@geogeo60715 ай бұрын
Not allowing square roots in the denominator is purely a matter of style.
@highpath47764 ай бұрын
but it makes it easier ? to compute an exacter number - the trick to multiply by a suitable substitution for 1 is something I would not have thought of
@kuplace19849 ай бұрын
Excellent class. Excellent job. Very knowledgeable in Math. Easy to follow and understand. Your chanel is a great resource. Thank you.
@AlfredBasso-z7h9 ай бұрын
I solved this in a second realizing that the answer would be less than 1.
@chrisjohngrima97618 ай бұрын
I don't if anybody had already said this but you could have done Sqrt(27)/sqrt(50) = sqrt(27)*sqrt(50)/sqrt(50)*sqrt(50) Sqrt(1350)/50 = sqrt(9)*sqrt(25)*sqrt(6)/50 Sqrt(9)*sqrt(25)*sqrt(6) = 3*sqrt(6)/10 Explanation: If your denominator is a root, you to get rid of the root without changing the value. For the first step, you can multiply the numerator and denominator by the sqrt(50) (Note that you can't sqaure both sides because that would give a different number eg sqrt(2)²/sqrt(3)² ≠ sqrt(2)*sqrt(3)/sqrt(3)*sqrt(3) ) After multiplying both by sqrt(50) you should get sqrt(50)*sqrt(27)/50. Our next step is to combine both root in to one root which would be sqrt(50*27)/50 = sqrt(1350)/50 After this, we should find the prime factors of 1350. Which is 1350=2*(3^3)*(5^2) Now we are only interested into getting the square numbers, now one of them is 5^2 but another one is 3^2 meaning we can rewrite this as 1350=6*(3^2)*(5^2) Which means, sqrt(1350)=sqrt(6)*sqrt(9)*sqrt(25) Because our denominator is 50, we can divide both side by the sqrt(25) giving us Sqrt(6)*sqrt(9)/±10 Next is to find the sqrt(9) which is ±3 So now our eqaution is, ±3*sqrt(6)/±10 Because there is ± both on the numerator and denominator we can cancel it out. Making our final answer, 3*sqrt(6)/10
@gavindeane36708 ай бұрын
That's impressively complicated (and you can drop the ± stuff as there's no ± here). Giving yourself the task of finding the prime factors of a number like 1350 when you can just see from inspection that 27 is 3×3² and 50 is 2×5² is a good one 😂
@Valerie-ek5ly8 ай бұрын
Thank you for another great video. Very well explained, and touching base on every step!
@Surreal_Wizard9 ай бұрын
Three-hooky thing -six on top of the horizontal bar, ten underneath
@harrymatabal84489 ай бұрын
Mr joseph. I agree with you 100%. Have a great day and may god bless you for helping math learners.
@robertstuart66459 ай бұрын
The hardest part of doing this problem is rationalizing the denominator. By applying the laws of radicals, the answer is simply (3x3^,5)÷(5×2^,5).
@lukeknowles57008 ай бұрын
I guessed the answer by approximating the original two square roots, and then comparing that estimate to the four choices of answers. Only one of the four could have been close, so although I forgot the details of solving this, I was confident just using approximations. But now I know how to solve it precisely!
@sharocooper6696 ай бұрын
Sqrt of numerator is smaller than sqrt of denomator; b is the only answer that fits..
@borstenpinsel9 ай бұрын
27 < 50, since both are >1 this means sqr27 < sqr50 which means the 0>result>1 which rules out all but b)
@flagmichael8 ай бұрын
... or "none of the above." Welcome to YT math.
@calvinmasters61595 ай бұрын
Fun. For once I didn't guesstimate first, but looked for factors in the original question. They just looked factorable. Once I had 3 root 3, and 5 root 2, the rest was just picking up the pieces.
@TheAZZA09907 ай бұрын
Really quite straightforward! b !!!
@erembald29279 ай бұрын
Not too sure about this bur here goes: 27^0.5/50^0.5 = (9^0.5 x 3^0.5)/ (25^0.5 x 2^0.5) = (3 x 3^0.5) / (5 x 2^0.5), multiply the square root components top and bottom by 2^0.5 = (3 x 6^0.5) / (5 x 4^0.5) = 3 x 6^0.5 / 10
@haraldreimann-trusheim29938 ай бұрын
why do i need to calculate anything? 27 SQRT(27)0) => SQRT(27)/SQRT(50) < 1 b) is the only solution 3*SQRT(6) < 9) Just 30 seconds to solve, because this is multiple choice
@icespeckledhens6 ай бұрын
Very good explanation, thanks
@chrisdissanayake69798 ай бұрын
This is his KZbin channel. So, we can’t be rude, picking on his style of teaching. Each of our minds are unique and each one operates the way it has been programmed and maybe according to the genes too. We have an advanced human brain to realize that and let’s be appreciative of what we are offered in life. Maybe there are some others who are not that smart as you all who complain, and they must be learning and benefiting from the hard work of this teacher. It is impossible to please everyone, when it comes to anything in this world. Maybe you all can have your own channel to display your expert math skills!
@Shay-q8u7 ай бұрын
Numerator: 27 is just 3 * 3 * 3 Denominator: 50 is just 5 * 5 * 2 Numerator is 3(3^1/2) Denominator is 5(2^1/2) we have a root in the denominator so we multiply: Numerator: (3 * 2)^1/2 gives us 3(6^1/2) Denominator (2 * 2)^ 1/2 5(4 ^ 1/2) is 5 (2) which is 10 Final answer [3(6 ^ 1/2)] / 10 This is answer b since 1/2 as exponent means square root.
@bravikumar89508 ай бұрын
Good explanation 👍👍
@jetman5516 ай бұрын
In John's defense, I needed to see the whole process. Now I get it.
@rcnayak_587 ай бұрын
Let us do it in a very simple way. The question is √27/√50. We can write it as √ (27/50) which also equal to √ (54/100). Let us convert all possible answers in this form. (a) 5√8 = √ 25. √8 = √ 200. (b) 3√6/10 = √9.√6/√100 = √(54/100) (c) √ 1350 (d) 8√6 = √ (64.6) √ 384. Clearly, the answer is (b).
@ChaosPod9 ай бұрын
Break each number into their prime factors, 27 = 3^3 and 50 = 2x5^2, so sqrt(27) = 3 sqrt(3) and sqrt(50) = 5 sqrt(2), then rationalise the denominator by multiplying by sqrt(2)/sqrt(2) and you’re done.
@LouisHansell8 ай бұрын
Correct answer can be seen at a glance of the choices. Square root of 27 is ~5, of 50 ~7. So the answer should be around .7, 5-7ths or ~5x.14. Answers a, c and d are too big to way-too-big. So only answer b remains. On second glance, you can see that answer b is 3/10 of square root of 6. if that was SR of 4, 2x.3 = .6. Close enough to .7. So you can get the correct answer easily.
@harrymatabal84489 ай бұрын
Excellent John sir thanks for telling us that you are teaching for s decade. Do you know that 1year experience multiplied by 10 is not the same as 10 years experience multiplied by 1.
@ericlipps94599 ай бұрын
It's (b). sqrt(27)/sqrt(50) = sqrt(27/50)=sqrt(54/100). Not take sqrt (1/100) outside the radical and you have sqrt(54)/10. 54 = 9*6, so you can take sqrt(9)=3 outside the radical. Now you have 3 sqrt(6)/10. Q.E.D.
@shakkazulu42379 ай бұрын
The answer is 3/5
@yingxinsun18707 ай бұрын
The answer is obviously less than 1, so only B is possible right
@OuryLN6 ай бұрын
It’s more that one forgets these rules since we don’t often use radicals and just simplify and estimate
@russelllomando84609 ай бұрын
got it B took some factoring & reducing thanks for the fun
@Cccoast9 ай бұрын
Is it weird that i love these problems ?
@rhigel22699 ай бұрын
Yes!
@moboutmen4 ай бұрын
My sixth grade teacher would have killed me if I got this wrong, 55 years later!
@caraswintelski41068 ай бұрын
Dear Mr Tablet I like to do two of these in the morning. I CANNOT spend 40 - 50 minutes doing this. PLEASE cut the running times in half or do two versions. Thank you. Dr S.
@davereynolds7397 ай бұрын
He always gives the correct answer at the beginning of his videos. If you get the correct answer, just don't watch the rest of the video.
@Rick_the_chemist9 ай бұрын
When a number is divided by a larger number, the answer is always less than one. Answer b is the only option less than one, so it is the correct answer. Simple logic.
@deltalima67039 ай бұрын
Thats how I got it but it seemed sus. Ran it through a calculator, and sure enough. Then realized 27 is 9 x 3 (god, idiot!) and the entire method was clear to me. Embarassing a little, so I gave him a thumbs up and watched the video as punishment. :)
@argonwheatbelly6379 ай бұрын
Just rationalize the denominator, factor, and reduce. Pretty simple.
@rdspam8 ай бұрын
It’s roughly 5/7 and only one answer choice isn’t >1.
@mrblakeboy14209 ай бұрын
the answer is obviously less than one, and three of the options are obviously more than one, but i’ll prove it anyway. it’s 3sqrt(3)/5sqrt(2), which is 3sqrt(3/2)/5. multiply both parts by 2(put the 2 in the square root) and you get 3sqrt(6)/10, which is answer choice b
@andyl80556 ай бұрын
Could only be b. The others are all greater than one.
@flagmichael8 ай бұрын
You did okay - a little long but you were taking the scenic route - up to 17:00. That was all you needed to do. Getting the radical out of the denominator is fine, but then why did you leave it as a fraction rather than converting it to 0.3 sqrt 6? A matter of taste, I suppose.
@Sailor376also9 ай бұрын
It can only be (b) It is about 5 divided by 7,, a value less than one. (a), (c), and (d) all have values greater than one.
@richardhole84299 ай бұрын
My method also.
@dougnettleton53269 ай бұрын
A great way to look at it, but I never assume that any one of the choices is necessarily correct. So, while it couldn't possibly be a), c), or d), I checked that b) was, in fact, the answer. I didn't watch the video because I don't want to know how a three step solution could take so long to explain: sqrt(27)/sqrt(50) => 3×sqrt(3)/(5×sqrt(2)) => 3×sqrt(3)×sqrt(2)/(5×sqrt(2)×sqrt(2)) => 3×sqrt(6)/10
@Sailor376also9 ай бұрын
@@dougnettleton5326 I like your method. Yours made immediate sense. I am a nuts and bolts kind of guy,, quadratic equations are not my thing.
@starman23374 ай бұрын
If Sqr Root of 2 is an invalid denominator, how can you multiply by a number with Sqr root of 2 in the denominator?
@rezamohamadakhavan_abdolla86278 ай бұрын
Thank you very much
@ddemoon-y3w9 ай бұрын
What's your number for a week maths lesson
@ccw84019 ай бұрын
never mind. You answered my question when I watched the video.
@johnnyrosenberg95229 ай бұрын
I didn't watch the video since it's over 20 minutes long. Here's my try, though: ✓1350 is definitely wrong. I can see an easy way to get 10 as denominator, so let's try that: ✓50=✓(100•½)=10✓½ ✓27=✓(3•9)=3✓3 (or, if you'd rather prefer, ✓27=✓3³=✓(3²•3¹)=3✓3) (3✓3)/(10✓½)=3✓(3/½)/10=3✓(3•2)/10=(3✓6)/10, so B it is. Now, looking at A and D I realize that I should have had a look at those before beginning to calculate, since they are both impossible answers to this question, but calculating is one of the fun bits in maths anyway, so I'm OK with that.
@Laneboy0077 сағат бұрын
Would of been interesting if one of the answers was say 2.7^2 instead of all but one of the answers being over 5
😅I don't know how to solve this mathematically but given a multiple choice option, it's clear that only b) comes close enough to my thinking which is sqr 27 is about 5, sqr 50 is about 7, 5/7 is about 0.7. Close enough to get the answer right using logic and a bit of arithmetic
@panlomito9 ай бұрын
An irrational in the denominator... V2/V2 will eliminate that culprit... V27 / V50 = 3V3 / 5V2 = (3V3 . V2) / (5V2 . V2) = 3V6 / 10
@shakkazulu42379 ай бұрын
The answer is 3/5
@tomekdluzniewski20859 ай бұрын
If we assume that one of the answers is correct, then the only one that is less than 1 is b, as is √27/√50
@sie_khoentjoeng48868 ай бұрын
Since √27 < √50, then √27 / √50 < 1, and the only answer that less than 1 is 3√6 / 10 (before I start to count it)
@koenigal9 ай бұрын
Answer B: factor out the squares 9 and 25, then multiple top and bottom by the square root of 2, and you get answer B
@skipbrewer81019 ай бұрын
3√3/5√2 gets the same answer. I will watch video for further simplification.
@tonywardle11409 ай бұрын
Like what you are trying to do...but found myself saying "just get on with it" Too repetative...
@jamav8r4 ай бұрын
He does tend to ramble a lot
@tamptus34798 ай бұрын
a c d are integer in some algebraic field sqrt(27) / sqrt(50) is never in integer so b is the only possible answer
@TheAZZA09909 ай бұрын
To be or not to be?!! b of course!! :)
@Ron_DeForest8 ай бұрын
Don’t make a big square root. Break down the top and bottom to 3 root 3 / 5 root 2. Rationalize the denominator then bring to lowest term. Way faster.
@RustyWalker9 ай бұрын
B, estimating with the roots of 25 and 49.
@bigdog36289 ай бұрын
and that is why you should never have multiple choice in mathematics.
@RustyWalker9 ай бұрын
@@bigdog3628 Especially when only one is possible
@shakkazulu42379 ай бұрын
The answer is 3/5
@shakkazulu42379 ай бұрын
The answer is 3/5
@glennmccarthy42643 ай бұрын
B is the answer after you rationalize the denominator.
@gerardfojas7693Күн бұрын
b) 3 SQRT (6) / 10 is the answer
@jackieadams61169 ай бұрын
Mr Math Man racialize with just •1, I’m never gonna forget how to rationalize the numerator or denominator. I want forget one.
@rubenfuentes2057 ай бұрын
b). 0,3 √6
@windy72599 ай бұрын
Easy: SR27 is 3SR3, and SR50 is SR100 divides by SR2. Thé result is so 3SR3 divides by SR(100 /2) , that GI es: 10/SR2, resulting in thé second solution.
@ramsinghbora16559 ай бұрын
Skipbrewer,pls rationalize the fraction which will come 6/10*_/6
@bigdog36287 ай бұрын
√27 is 3√3 √50 is 5√2 we can't have a √ in the denominator so multiply top and bottom by √2 numerator is 3√6 denominator is 5 (2) or 10 Can't reduce further so (3√6)/10 is the answer.
@normhardy9 ай бұрын
The only option that makes sense is b. It is less than 1, which is clear from the original question.
@shakkazulu42379 ай бұрын
The answer is 3/5
@robertgraybeard37507 ай бұрын
All the answers except (b) are clearly larger than one while the answer must be smaller than one. I had to watch the video to remember the "trick" of getting to (b).
@aljjeeran8 ай бұрын
b)3square6over 10
@bobbresnahan83977 ай бұрын
3/5/square roots 3 + 2
@robertstratton18389 ай бұрын
Easy to answer since it has to be less than 1 a fraction. None of other answers are less than one.
@murdock55379 ай бұрын
√27/√50 = 3√3/5√2 = 3√6/10
@MimiMimi20_094 ай бұрын
I’m so glad I was not one of your students not sure why you go around and around to explain how to find the solution 🙄
@gordonspond7 ай бұрын
Since the answer is less than one, 3 of the possible answers can be eliminated without doing any algebra.
@ramesankd16042 ай бұрын
5.3.14
@jayantabanerjee68643 ай бұрын
Option 'b' is correct
@shivanandaaithal48189 ай бұрын
Simple calculation the answer is less than 1. So b is the answer
@pandurangaraonimmagadda99669 ай бұрын
3. Root of 3/5 root of 2= (3.root 3.root 2)/(5.root 2.root 2)=(3 root 6)/10 , So answer is😅 (b)
@EricWells-s2p6 күн бұрын
Two steps, only. 3^6/10
@TH-12079 ай бұрын
Wow you sure went through a lot more steps than necessary. You were almost done when you had the fraction under the radical. Here you multiply the numerator and denominator by 2 and then take it back apart so the denominator is sqrt of 100 and numerator is sqrt if 54. The numerator then factors into 3 time sqrt 6 and denominator becomes 10. The hint for this approach is in the answers. 50 is half of 100 and 10 is the sqrt of 100. Actually just recognizing this lets you know that (b) is the only correct answer.
@shakkazulu42379 ай бұрын
The answer is 3/5
@barney20017 ай бұрын
multiple choice. you don’t solve the problem, you eliminate answers that it couldn’t be.
@Shay-q8u7 ай бұрын
this is exactly why in my country you NEVER have multiple choice in Math unless show your work is required. I actually had a challenge for my class once when they begged me to have a multiple choice test. I told them I would do one, but they would have to show each and every step NOTHING in there head. In exchange any student who got the questions 100% right would have their grade raised a full letter and anybody who got even one wrong answer would have their grade lowered one full letter. To be fair the test was optional and they did NOT have to take my challenge. All of them accepted though. I threw a curve ball on one of the questions and did NOT have the proper answer listed. Only 2 students of a class of 18 got their grade raised everyone else didn't even come close to getting it and I did NOT need to throw the curve ball.
@shakirhamoodi50096 ай бұрын
b) 3 sqrt(6) /10 It took me one minute
@mylittlepitbull31439 ай бұрын
How to make a simple problem hard.
@shakkazulu42379 ай бұрын
The answer is 3/5
@maxinemcafee48939 ай бұрын
Got b. Wow got it right!
@bjorneriksson64808 ай бұрын
I did not understand why you could not have an irrational number as denominator?