Question

Alan is participating in a 4-day cross-country biking challenge. He biked for 62, 49, and 51 miles on the first three days. How many miles does he need to bike

on the last day so that his average (mean) is 56 miles per day?

Answer 1

62 miles

Explanation:

Let x be the number of miles needed on the last day for the mean of 56 miles per day.

If 56 miles per day is the mean over 4 days, then the mean can be written as:

mean = 56 = (62 + 49 + 51 + x) / 4

Isolate x.

56 * 4 = (62 + 49 + 51 + x) / 4 * 4

224 = 62 + 49 + 51 + x

x = 224 - (62 + 49 + 51) = 62