Question

If the arithmetic mean of two items of a series is 12.5 and geometric mean is 10, what is the difference of the two items? [Delhi Univ. B.Com.(p) 2004

Answer 1

Explanation:

Let the numbers be x and y.

x+y = 26 …(1)

xy = 144 …(2)

x(26-x) = 144, or

x^2–26x+144 = 0

(x-18)(x-8) = 0

So x = 18 and y = 8.

The two numbers are 18 and 8.