The average of two numbers is π/2...

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The average of two numbers is π/2...

by swerve » Mon Oct 30, 2017 9:19 am
The average of two numbers is π/2, and one of the numbers is x. What is the other number in terms of x?

$$(A)\ \frac{\pi}{2}−x$$
$$(B)\ \frac{\pi}{2x}$$
$$(C)\ \pi−x$$
$$(D)\ \pi+x$$
$$(E)\ 2\pi+x$$

The OA is C.

I don't understand why C is the correct answer. Please, can any expert explain this PS question? Thanks.
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by [email protected] » Mon Oct 30, 2017 2:16 pm
Hi swerve,

We're told that the average of two numbers is π/2 and that one of the numbers is X. We're asked for the other number (in terms of X).

Since we're averaging 2 numbers (with the 2 numbers as X and A), we can set up the Average Formula:

(X + A)/2 = π/2

Now we just have to do a couple of 'math steps' to solve for A....

(X + A) = (2)(Ï€/2)
(X + A) = π
A = π - X

Final Answer: C

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