mmelendez wrote:
Given s and t are integers greater than 1 and t<s, what is the value of \(s^2t-st^2\) ?
Statement 1, \(t\) is a prime number
Statement 2, \(st=15\)
Kudos if you like this question and the answer I will give
Please follow posting guidelines (link in my signatures) or else I will have to delete the question. No emoticons or unnecessary text in the question. Topic should be a lot more than first 2-3 words. Your original question talked about s and t being greater than and then you mention they are greater than 1 as well. It only needs to mention that both s,t are >1.
Also, prime can ONLY be integers and as such mentioning both in statement 1 is redundant. GMAT language is a lot more subtle and to the point.
As for this question,
\(s^2t-st^2\) = ? with s and t \(\in\) integers > 1.
Per statement 1, t= prime number . Too many options for t and no clue about s, making this statement not sufficient.
Per statement 2, st=15 ---> as both s and t>1 and 15 has 1,3,5,15 as the factors, only (3,5) or (5,3) will work as (s,t) pair. But it is also given that s>t and thus (3,5) is eliminated , giving us the only possible values of s,t as 5,3 and hence you will get a unique value of \(s^2t-st^2\) (no need to solve this final unique value).
This statement is sufficient.
B is the correct answer.