GRE Quant Ep 16: Number Properties

[@alejandras5586]

Q7 method was fantastic! Thank you so much

[@GRENinjaTutoring]

Thank you! I'm glad that you enjoyed it. Have fun studying!

[@nolan_meyer]

mistake at 1:04:49 odd + odd = even e.g. 7 + 5 = 12

[@andrewn247]

At 40:23, how did you decide to input evens to start? x can be even or odd, so how did you decide to start with the more efficient choice of testing evens first?

[@smitpatel9995]

LCM Easy method Find LCM of 18 and 24. Factors: 18:- 2x3x3 24:- 2x2x2x3 Now cancel out the commons: 18:- 3 24:- 2x2 Finally, cross multiply: 18 x (2x2) = 72 24 x (3) = 72 You don't even need to cross multiply both. Just go for one of them and that's the LCM. Different logic: If we wanna do this: (1/18) + (1/24) = (1/2x3x3) + (1/2x2x2x3) = (2x2/2x3x3x2x2) + (3/2x2x2x3x3) same denominator, = 2x2/72 + 3/72 Denominator is the LCM.

[@jesszilla2363]

At 41:20, the answer choice D is miscopied from the problem. It starts with x^3, not x^2.

[@martynadydyk9714]

Praying for the last question to be on my GRE, it was the easiest one in this series.

[@shambhuchaudhary8371]

Was it on your GRE?

[@martynadydyk9714]

​@shambhuchaudhary8371 I ended up not doing it after all. I just didn't think I'd get good enough score so I applied to universities that don't require it

[@shambhuchaudhary8371]

@@martynadydyk9714 oh, cool mate, did you get in?

[@matveykokin4879]

1:04:50 - how is odd + odd is odd? Secondly, can you also consider p = zero cause zero is an integer?

[@merterenagcabay4263]

Yes you are right. It should be stated in the question but p cant be zero cuz qr cant be odd and even at the same time which is contions of questions.

[@prabeshkhanal5273]

Great video

[@GRENinjaTutoring]

Thank you!

[@saranidal9029]

there is an easier way to deal with the last question by reducing it to one expression only. try subtracting both expressions you get p-pq which is p(1-q). and since this expression is the result of odd - even, it should be odd. Now p(1-q) has to be odd and this happens only if p is also odd. because if p is even then multiplying by any value of (1-q) will give you even, but we know that this multiplication result has to be odd.

[@MohammedAqar]

Are these GRE questions difficulty level the same as the real GRE test?

[@GRENinjaTutoring]

We did all we could to make these questions as close to the real thing as possible while still covering the content you'll need to know for the GRE. As Alex says from about 1:20, the questions in the video will start off easy, get progressively more difficult as the video progresses, and will end with a couple of questions that are equivalent to the kind of question you'll need to score 168+. I hope that helps!

[@dattaraj-d]

Why didn't you consider o e e as option

[@merterenagcabay4263]

@@dattaraj-d o e e option does not change the answer of question cuz p is odd anyway.

[@Anishshrestha-x7c]

I can do all these question easily. What is the difficulty level ?

[@farahbasmagi425]

For the last question, doesnt p have to be even, because if p is odd in the first equation (p+qr=odd), it will be odd + odd which = even.

[@GRENinjaTutoring]

It's hard to explain this here using just text, but I'll see what I can do. For the first equation p + qr = odd, we have the following options: p -- e - o - o - o q -- o - e - o - e r -- o - o - e - e If p is odd in this equation, qr must be even. There are three possibilities for this, as listed above. Then, we can look at the second equation pq + qr = even. We could factor out a q to give q(p + r) = even. This gives us the options listed below. The first two options are what we get if q is odd, the remainder are if q is even. p -- e - o - e - e - o - o q -- o - o - e - e - e - e r -- e - o - e - o - e - o There are only two options that appear in both lists: p -- o - o q -- e - e r -- e - o In both of these cases, p must be odd. This is why (B) is the answer to this question. I hope that helps!

[@ugonnaumeh2259]

for question 2 what if they are not integers instead de and ef are -0.1 and -0.2 wont zero be bigger so i believe the answer is d

[@GRENinjaTutoring]

Thinking about whether the numbers are positive or negative, as Alex did in his explanation, works whether the numbers are integers or decimals. If ef = -0.1 and de = -0.2, then either we know that d and f are positive and e is negative or we know that d and f are negative and e is positive. In either of those cases (d^5)(e^2)(f^3) will be positive, so the answer to this question is (A). I hope that helps!

[@tamimhasan2195]

You can solve the last question in 20 sec P + qr = odd ……(1) Pq + qr = even ……..(2) (1)-(2) P- pq = odd P(1-q) = odd P and (1-q) nust be odd So -1^odd = -1 Thats less than 0 So answer is B

[@mariamlotfy932]

HOW ABOUT P=O, Q=E, and R=E?

[@GRENinjaTutoring]

I think you're asking about the final question, but please let me know if I've got that wrong. You're right: that's another scenario that would satisfy the conditions given in the question. The good news is that p is still odd in this scenario, so (-1)^p = -1, and the answer to this question is still (B). Thank you for your comment!