Data Sufficiency

lionsshare wrote:What is the value of n in the equation -25 + 19 + n = s ?

(1) s = 2
(2) n/s = 4

Target question: What is the value of n?

Given: -25 + 19 + n = s
Since we're trying to find the value of n, let's solve the given equation for n

First, simplify left side to get: -6 + n = s
Add 6 to both sides to get: n = s + 6

Statement 1: s = 2
Great!
We already know that n = s + 6
If s = 2, we can say that n = 2 + 6
So, n = 8
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: n/s = 4
Multiply both sides by s to get: n = 4s
Divide both sides by 4 to get: n/4 = s
Now take n = s + 6 and replace s with n/4
When we do this we get: n = n/4 + 6
Multiply both sides by 4 to get: 4n = n + 24
Subtract n from both sides: 3n = 24
Solve: n = 8
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent