Question

The average of a non-zero number and its square is 5 times the number. The number is

• A. 3
• B. 6
• C. 9
• D. 12

Answer 1

Answer: (C)

9

Let the number be x. Then,

(x + x${}^2$)/ 2 = 5x

$\Rightarrow$ x${}^2$ - 9x = 0

$\Rightarrow$ x (x - 9) = 0

$\Rightarrow$ x = 0 or x = 9.

So, the number is 9.