Sir, I have seen many video lessons from GMAT club and other sources. But I must say, Wizako quant and verbal videos, both are the best i have come across.
Hi sir, in question number 3 is there a way to solve without counter examples? How do you know when to stop. I found counter examples in all cases except combination so marked C. Any safer way to solve.
Sir for the first question ; though I thought in exactly the same way & got the answer as C ; but I have a doubt that when the value becomes -6.9 ; it is devisible by 3 i.e the co-efficient is -2.3 & remainder is 0 ; so y we are not considering that?
Hello Aditya. That is a common mistake most of us make. The quotient has to always be an integer. It can never be a non-integer. So, -2.3 is the value of dividing -6.9 by 3. However, the quotient of the division will be -2 and the remainder will be -0.9. No non-integer is divisible by an integer.
Sir in Q.3, What if you take the value of p as an integer like 10,12 etc and q as a non integer like 2.5, 5.5 etc. I mean my question is can we take all possible values to get to "p+q" where p may be different and q is also different? The way you took 10 as p and 2 as q and then you again took non integers like 10/3 and 2/3, CAN WE TAKE 10/3 & 2/4?
Hi Akshit, If you take P and Q as 10/3 and 2/4 respectively then the question statements 1 & 2 itself will be invalid, i.e., (P - Q) and (P + 2Q) will not be integers. Our requirement is to take values of P and Q in such a way that (P - Q) and (P + 2Q) will be integers and THEN find out whether (P + Q) is an integer or not. If you still have any doubts, do comment below. Best wishes for your GMAT!
Hi Sir, for the variant in Q2, I got answer C (both statements together are sufficient). Could you tell me if my logic is correct? Statement 1 gives us value as +/-3 and statement 2 gives us N>2.2.5. Therefore, N cannot be -3 and must be +3. So we have a unique answer (ie: No) to the target question. Is my logic correct?
When we say divisible, it means that the quotient is an integer and the remainder is 0. So, 6.9 by 3 will result in the quotient being 2 and the remainder being 0.9 Please do not equate this to be same as the value of 6.9 divided by 3 being 2.3 Another example. An odd number is not divisible by 2. We all know 7 is an odd number. But 7 by 2 is 3.5 - that does not make 7 a number that is divisible by 2. When 7 is divided by 2, the quotient is 3 and the remainder is 1. Hope this helps clarify the point. Please ping back if you still have misgivings about this point.
When all the questions are displaying together, the first one asks to check divisibility by 7 whereas later it has asked to check it by 3. There is a correction I guess. Thanks.
Finding the correct counter examples takes a while to implement. Do not get disheartened. What you can do, especially with number properties questions, is to be aware of all common possibilities. Integer or not? positive, negative, or zero? rational or irrational? and so on. If you have a checklist of different things to check for, and check only those relevant to the question (for example, if the questions already says X is an integer, do not frame examples with X as a non-integer), then you will become better and better at framing counter examples. Good luck!
Sir, I have seen many video lessons from GMAT club and other sources. But I must say, Wizako quant and verbal videos, both are the best i have come across.
beautiful questions
I keep on making silly mistakes..
Explanations to these questions are so engaging
Hello Kalyan
Thanks for your feedback. Have posted today's DS questions. This set of 2 questions are from Geometry.
Hi sir, in question number 3 is there a way to solve without counter examples? How do you know when to stop. I found counter examples in all cases except combination so marked C. Any safer way to solve.
Sir for the first question ; though I thought in exactly the same way & got the answer as C ; but I have a doubt that when the value becomes -6.9 ; it is devisible by 3 i.e the co-efficient is -2.3 & remainder is 0 ; so y we are not considering that?
Hello Aditya.
That is a common mistake most of us make. The quotient has to always be an integer. It can never be a non-integer. So, -2.3 is the value of dividing -6.9 by 3. However, the quotient of the division will be -2 and the remainder will be -0.9.
No non-integer is divisible by an integer.
Thank you so much sir🙏🏻
Glad it helped Gaurav! Cheers!
Sir in Q.3, What if you take the value of p as an integer like 10,12 etc and q as a non integer like 2.5, 5.5 etc. I mean my question is can we take all possible values to get to "p+q" where p may be different and q is also different?
The way you took 10 as p and 2 as q and then you again took non integers like 10/3 and 2/3, CAN WE TAKE 10/3 & 2/4?
Hi Akshit,
If you take P and Q as 10/3 and 2/4 respectively then the question statements 1 & 2 itself will be invalid, i.e., (P - Q) and (P + 2Q) will not be integers.
Our requirement is to take values of P and Q in such a way that (P - Q) and (P + 2Q) will be integers and THEN find out whether (P + Q) is an integer or not.
If you still have any doubts, do comment below. Best wishes for your GMAT!
sir,
what is the best way to reduce time spent of such DS questions. or what should be the optimal time for these questions ?
Hi Sir, Could you post the answer to the variant question for Q2? Want to check whether my answer is correct. Thanks!
For the variant, the correct answer is choice C. Both statements are required to answer the question.
Hi Sir, for the variant in Q2, I got answer C (both statements together are sufficient). Could you tell me if my logic is correct? Statement 1 gives us value as +/-3 and statement 2 gives us N>2.2.5. Therefore, N cannot be -3 and must be +3. So we have a unique answer (ie: No) to the target question. Is my logic correct?
Sir, even decimals are considered divisible right? In this case, ST2 alone should be sufficient. Can you pl clarify?
When we say divisible, it means that the quotient is an integer and the remainder is 0.
So, 6.9 by 3 will result in the quotient being 2 and the remainder being 0.9
Please do not equate this to be same as the value of 6.9 divided by 3 being 2.3
Another example. An odd number is not divisible by 2. We all know 7 is an odd number. But 7 by 2 is 3.5 - that does not make 7 a number that is divisible by 2.
When 7 is divided by 2, the quotient is 3 and the remainder is 1.
Hope this helps clarify the point. Please ping back if you still have misgivings about this point.
@@Wizako Sir, thank you very much. It is clear to me now.
When all the questions are displaying together, the first one asks to check divisibility by 7 whereas later it has asked to check it by 3. There is a correction I guess. Thanks.
Hello Anas,
Indeed, good catch.
Thanks for pointing it out.
I always mess on finding the right counter examples 😢
Finding the correct counter examples takes a while to implement. Do not get disheartened.
What you can do, especially with number properties questions, is to be aware of all common possibilities. Integer or not? positive, negative, or zero? rational or irrational? and so on. If you have a checklist of different things to check for, and check only those relevant to the question (for example, if the questions already says X is an integer, do not frame examples with X as a non-integer), then you will become better and better at framing counter examples. Good luck!
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