Data Sufficiency

VJesus12 wrote:Division R of Company Q has 1,000 employees. What is the average (arithmetic mean) annual salary of the employees at Company Q?

(1) The average annual salary of the employees in Division R is $30,000.
(2) The average annual salary of the employees at Company Q who are not in Division R is $35,000.

[spoiler]OA=E[/spoiler]

Source: Official Guide

Say

the number of employees at Company Q who are in Division R is R and their average salary is given by $r.
the number of employees at Company Q who are not in Division R is X and their average salary is given by $x.

Thus,

The average (arithmetic mean) annual salary of the employees at Company Q = (R*r + X*x) / (R + X) = (1,000*r + X*x) / (1,000 + X)

We have to get the value of (1,000*r + X*x) / (1,000 + X).

Let's take each statement one by one.

(1) The average annual salary of the employees in Division R is $30,000.

(1,000*r + X*x) / (1,000 + X) = (1,000*30,000 + X*x) / (1,000 + X). Since we do not know that value of X and x, we can't get the answer. Insufficient.

(2) The average annual salary of the employees at Company Q who are not in Division R is $35,000.

(1,000*r + X*x) / (1,000 + X) = (1,000*r + X*35,000) / (1,000 + X). Since we do not know that value of X and r, we can't get the answer. Insufficient.

(1) and (2) together

(1,000*r + X*x) / (1,000 + X) = (1,000*30,000 + X*35,000) / (1,000 + X). Since we do not know that value of X, we can't get the answer. Insufficient.

The correct answer: E

Hope this helps!

-Jay
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