The average (arithmetic mean) and median of the five numbers a,a,b,c, and c are 20 and 30, respectively. If a < b < c, what is the value of a + c?

Answer 1

5 numbers: a, a, b, c, c

mean = 20
--> (2a + b + 2c)/5 = 20
2a + b + 2c = 100

median = 30
---> b = 30

so we have
2a + 30 + 2c = 100
2a + 2c = 70
a+c=35