Five different whole numbers have a median of 20. When the largest of them is doubled, their mean rises by 6. What is the largest number?

Explanation

1. 01

   Doubling the largest number L adds L to the total.

2. 02

   The mean rises by $L \div 5 = 6$, so $L = 30$.

3. 03

   The median is not needed; it only tells you L is more than 20, which 30 satisfies.