When n is divided by 4, what is the remainder?
1) When n is divided by 3, the remainder is 1
2) When n+1 is divided by 4, the remainder is 2
==> In the original condition, there is 1 variable (n) and in order to match the number of variables to the number of equations, there must be 1 equation. Since there is 1 for con 1) and 1 for con 2), D is most likely to be the answer. For remainder questions, you can directly substitute. Therefore, for con 1), from n=3p+1=1,4,…, the remainder when divided by 4 becomes 1=4(0)+1, which makes remainder=1, and from 4=4(1)+0, you get remainder=0, hence it is not unique and not sufficient. For con 2), from n+1=4q+2 and n=4q+1, the remainder when divided by 4 always becomes 1, hence it is unique and sufficient.
Therefore, the answer is B.
Answer: B
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spareThe one-and-only
World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $69 for 1 month Online Course""Free Resources-7 day online access & Diagnostic Test""Unlimited Access to over 120 free video lessons - try it yourself"