Question

If a < b < 2a and the mean and median of a, b and 2a are 15 and 12 respectively, then a = ______.

Answer 1

If a < b < 2a and the mean and median of a, b and 2a are 15 and 12 respectively, then a = 11.

Explanation:

Since a < b < 2a, the median is b, so b = 12.

The mean gives \[\frac{a+b+2a}{3}=15\] or 3a + b = 45.

Substituting b = 12 gives a = 11.