2700, took me 1 minute using excel. Set all the numerators as 1 for all, then add them up. Divide 200 by the sum and you get 2700. I wish I was better at doing the proper math.
21=3*7,77=7*11,165=11*15⋯⋯This is the most important facts. Base on this hints, 4=7-3 =11-7=15-11=…, then students could find out the way to solve by themselves. How you can find this facts is the most important thing in this problem. But you just treat it as nothing, so you did teach nothing.
@noobbot70996 ай бұрын
much longer method just write nth term which is 1/(4n-1)(4n+3) and put values after creating difference
A very nice exercise. The trick is pretty ingenious.The execution was a little tedious, though. Under inspection it was clear that b-a was equal to 4 in every term so that the factor 1/4 could be pulled in front.
@vijaymaths54836 ай бұрын
Thank you
@SergiuCosminViorel6 ай бұрын
solved, another way, three groups, 1&2, 3&4, 5&6, then one group, 1&3, plus one, solved
@JPTaquari7 ай бұрын
I know that the professor is going to use a complex method, which he knows, but I'm going to simplify it, and solve it in 5 or 10 minutes with a pencil and paper: Divide all denominators by 621, obtaining: 29.57 + 8.065 + 3.764 + 2.179 + 1.421 + 1 = 46 Then it's soft: 46 * X = 200 * 621 X = 2,700 Bingo from Brazil !
@vijaymaths54837 ай бұрын
Excellent ;)
@vishwasdeshpande39216 ай бұрын
Excellent
@rangaswamyks82876 ай бұрын
wow
@GWaters-xr1fv6 ай бұрын
Not excellent. This is just a decimal approximation method ( correct to two dec. places ) NOT an exact solution. The fact that your decimal rounding errors just happened to cancel out was a happy coincidence, which will usually not be the case.
@JPTaquari6 ай бұрын
Man, here in Brazil, they teach that good mathematics is the one that has the shortest path. I think you must have some mental, cognitive problem. Go treat yourself!
@beautifulmindinpuzzles77166 ай бұрын
At 4:59 multiply both sides by 4. RHS=800 and LHS will contain fractions like 4/(3x7) which is equivalent to [1/3 - 1/7]. Calculations will be a lot easier.
@crandoQcat6 ай бұрын
11:47 only use the least common denominator of 3&27 is 27。
When at first glance it is seen that each of the denominators is a product of two numbers like n and n+4 ,then it would be simpler to multiply both sides by four at the outserand then proceeding as x/3-x/7+x/7-x/11 and so on---
@santoshjha9206 ай бұрын
Thanks 🙏
@lnmukund61526 ай бұрын
Your atsite mental one line observation is superb, If u read solutions u can solve probs, but if u observe probs , u can create solutions thank u very much sir Mukund
@Andrumen015 ай бұрын
I don't understand why the trouble of numerical problems....they are just numbers... calculators are good at getting those numbers. Real olympiad problem would be proof based!
@demetrioalbuquerque54087 ай бұрын
Ótima resolução grande Mestre!! Mestre de onde é esse problema tão bonito?
@vijaymaths54837 ай бұрын
Thank you ⚘️
@user-ti2us8tj3e6 ай бұрын
این نوع مسائل در زمانیکه سال آخر دبیرستان بودم در کتاب حساب استدلالی بود حساب استدلالی درس جالب و خوبی بود ولی حالا دیگه در دبیرستانها تدریس نمیشه، حساب استدلالی در واقع درس هوش است و مسائل ابتکاری حل میشود
@vijaymaths54836 ай бұрын
Thanks for your sweet memory 🍫
@sumit-mn6ys7 ай бұрын
Nice Explanation 👍
@vijaymaths54837 ай бұрын
Thanks 🙂
@luislopez49046 ай бұрын
Excelente explicación
@Rocio621547 ай бұрын
X=2700
@vijaymaths54837 ай бұрын
right!!
@user-it6fh7hy6t7 ай бұрын
У автора какая то мания решать простейшие задачи труднейшим способом. 14 минут решает задачу,которую можно сделать за 3 минуты.
@vijaymaths54836 ай бұрын
I think method of simplification is more important
@Ekakshpareek947 ай бұрын
Totally wrong way. It's rather than simplifying/solving , the teacher is making it's complicated & getting more inconvenient
@WhiteGandalfs7 ай бұрын
It's a trade-off: You have to decide if you want to go the way with drastically less analytic writing, thus drastically reducing the probability of errors doing the analytical reformation, or to go the the way of drastically less numeric writing (after hopefully correctly completing the analytic reformation), thus minimizing the probability of errors doing that numeric stuff. Since as long as you do not know the OUTCOME of the analytical reformation, depending on your average error probability, you can make rather many errors in that analytical reformation, and since as long as you don't know the outcome (because you invented the riddle or you happen to be familiar with that exact type of reformation by chance) you typically go at least a few unsuccessful lanes down before featuring out the successful one, if you are not truly familiar with the way the author is suggesting here, you are by far better off going the numeric way directly, since it is really trivial in this case.
@Danieswors7 ай бұрын
@@WhiteGandalfs Indeed ! It's all about the whole process of solving a problem in different types of method , while the author doesn't shows the shortcut he's trying to crack the problem in alternative ways although it may be to long in competitive exams , but that shows we can also have a solution in well mannered followed steps atlast the solution is same it doesn't matter at all , it all depends on person to person by which method he/she needs to solve just stick to basic steps and bingo you will have the solution maybe you can have solution earlier , but we should know all the ways of method to end up giving a perfect answer.
@vadim648416 ай бұрын
I disagree. The solution avoids massive amount of computations. It takes time to explain, but if you understand the idea you can skip all these explanations and arrive to answer pretty quickly. What exactly would be a “straightforward” solution - finding a common denominator? Lots of multiplications and additions? This would be insane, and very easy to make a mistake.
@rainerinedinburgh58076 ай бұрын
@@vadim64841 Vijay's trick is brilliant, but there is a "straightforward" way that doesn't need massive amounts of computation. Instead of using the common denominator 3·7·11·15·19·23·27 of all six fractions, just add them pairwise, and as if by magic, plenty will just cancel out. 1/(3·7) + 1/(7·11) = (11+3=14)/(3·7·11) which simplifies to 2/(3·11) = A 1/(11·15) + 1/(15·19) = (19+11=30)/(11·15·19) which simplifies to 2/(11·19) = B 1/(19·23) + 1/(23·27) = (27+19=46)/(19·23·27) which simplifies to 2/(19·27) = C Now we only have to work out A+B+C = 2/(3·11) + 2/(11·19) + 2/(19·27). Again I combined just the first two to begin with instead of all three at once: A+B = 2/(3·11) + 2/(11·19) = 2(19+3=22)/(3·11·19) = 4/(3·19). And finally add C: 4/(3·19) + 2/(19·27) = (4·27+2·3)/(3·19·27) = 2(54+3=57=3·19)/(3·19·27) = 2/27. Putting that back into the original context, we get x·(2/27) = 200, and so x = 27·200/2 = 2700.
@gerardvanwilgen99176 ай бұрын
"This would be insane, and very easy to make a mistake.?"@@vadim64841 That is why electronic calculators were invented, but I do not know if those are allowed in competitions.
@ncslovers34297 ай бұрын
👌👌👌
@vijaymaths54837 ай бұрын
thanks for watching!!
@superiorlyrics83267 ай бұрын
👏👏👏
@crazyindianvines14726 ай бұрын
Great explanation 😀
@vijaymaths54836 ай бұрын
Glad you think so!
@pauloenockmarquesdasilva76436 ай бұрын
Show. Thank you very much!!!!
@vijaymaths54836 ай бұрын
You are welcome!
@user-hr9lv4gt8i5 ай бұрын
good!
@tonyennis17876 ай бұрын
Very nice indeed
@ToanPham-wr7xe6 ай бұрын
😮
@adroaldoferreira9787 ай бұрын
Uma boa questão de fatoração.
@vijaymaths54837 ай бұрын
Thank you
@YvanMcMillan6 ай бұрын
incredible !
@vijaymaths54836 ай бұрын
Thanks you !
@jatintrivedi56326 ай бұрын
Too much noise in baxkground.
@arifustatsonmez15576 ай бұрын
Thanx
@vijaymaths54836 ай бұрын
Thanks too for watching my Vijay Maths channel 💗
@kalakla6 ай бұрын
Are you serious teacher, what is this about .. it does not even get you likes or enough responses.
@ridaoueld59396 ай бұрын
Intéressant pour le calcul
@OscarGarcia-xy4xv6 ай бұрын
Eligió el camino largo..
@comdo7776 ай бұрын
asnwer=1x
@tanernays4326 ай бұрын
нашел общий щнаменатель за 2 минуты ЫЫЫЫЫ
@sannygs5 ай бұрын
U r messing up d students... totally wrong way
@yokdilyds81836 ай бұрын
Do you have to explain it one by one to make the video longer? I was almost afraid that he would explain the multiplication tables from the beginning. Don't treat your subscribers like such idiots. Even if there are idiots, they can't understand this problem