I was trying some practice questions online when I came across 2 tough ones.

**QUESTION 1**

1. Is y = 3?

(1) (y - 3)(x - 4) = 0

(2) (x - 4) = 0

Correct Answer: (E).

I'm not sure how they determined the answer to be E. I think it should be A because in statement 1, if each factor is set equal to 0, solving for y in the first factor gives you 3. Solving for x gives you 4 (but this is irrelevant to the question being asked).

**QUESTION 2**

If p is a prime number greater than 2, what is the value of p?

(1) There are a total of 100 prime numbers between 1 and p+1

(2) There are a total of p prime numbers between 1 and 3912

Correct Answer: (D).

I didn't really know where to begin with this question. I tend to get overwhelmed/intimidated by questions that provide very large numbers of values between 1 value and the other (i.e. 100 prime numbers between 1 and p+1). Would there be an efficient approach that I can use for all such questions (whether or not I am dealing with prime/non prime #s)?

Please let me know where I'm misinterpreting the information/how I could improve on such "solve for this variable" data sufficiency problems.

Thank you very much!

Krithika