Data Sufficiency

Hi, need help verifying answer to this question from manhattan cat exam.

If 72 cupcakes must be divided equally among the students in a certain class, how many students are in the class?

1) If the number of students is reduced by one-third, each student will receive 3 more cupcakes.
2) If the number of cupcakes is doubled, each student will receive 12 cupcakes.

I am getting (B) as my answer, as my equation for S1) is quadratic.... this right?

IMO D.
What's the OA?

IMO: D

1 Satisfies for 72/12 (6 cakes) -> 72/9 (9 cakes)

unprez wrote:Hi, need help verifying answer to this question from manhattan cat exam.

I am getting (B) as my answer, as my equation for S1) is quadratic.... this right?

What equations are you using to get a quadratic? Here is one way to solve it using only statement 1....

Let S=number of students, let N=number of cupcakes per student.

Given: 72/S=N or 72=SN

S1: 72/(2S/3)=N+3 ---> 108/S=N+3 ----> 108=SN+3S ----> 108-3S=SN

Now we have two expressions that are equal to SN. Set them equal to each other to get 108-3S=72. Solve for S=12.