If n is an integer between 3 and 9, what is the value of n ?

[BTGModeratorVI]

If n is an integer between 3 and 9, what is the value of n ?

(1) On the number line, the distance from 3 to n is 2/3 of the distance from 3 to 9.
(2) On the number line, n is 10 units to the right of -3

Answer: D
Source: official guide

[Brent@GMATPrepNow]

If n is an integer between 3 and 9, what is the value of n ?

(1) On the number line, the distance from 3 to n is 2/3 of the distance from 3 to 9.
(2) On the number line, n is 10 units to the right of -3

Answer: D
Source: official guide

Given: n is an integer between 3 and 9
In other words, the number line looks like This: <------3-----n------9------>

Target question: What is the value of n ?

Statement 1: On the number line, the distance from 3 to n is 2/3 of the distance from 3 to 9.
We can write: (n - 3) = (2/3)(9 - 3)
Since this is a linear equation with only one variable, we COULD to find the value of n (but we would never waste precious time on test day doing so)
Since we COULD answer the target question with certainty, statement 1 is SUFFICIENT

Aside: If we solve the equation we get n = 7

Statement 2: On the number line, n is 10 units to the right of -3
In other words, n = -3 + 10
In other words, n = 7
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent