stonecold wrote:

In a set of three variables, the average of the first two variables is greater than 2, the average of the last two variables is great than or equal to 3 , the average of the first and third variable is 4.Which of the following could be the average of the three variables?

A)1

B)1.5

C)2

D)3

E)3.5

We can let the three variables be a, b and c. So we have:

(a + b)/2 > 2

a + b > 4

and

(b + c)/2 ≥ 3

b + c ≥ 6

and

(a + c)/2 = 4

a + c = 8.

If we add up these three inequalities/equations, we have:

2a + 2b + 2c > 18

a + b + c > 9

(a + b + c)/3 > 3

The only number is greater than 3 is 3.5, thus it’s the answer.

Answer: E

_________________

Jeffery Miller

Head of GMAT Instruction

GMAT Quant Self-Study Course

500+ lessons 3000+ practice problems 800+ HD solutions