Question

At the end of each day, a driver works out the mean distance they have driven so far that week.

At the end of 5 days, the mean distance they have driven is 185.5 miles per day.
At the end of 6 days, the mean distance they have driven is 190 miles per day.

Work out how many miles the driver drove on the sixth day of that week.

Answer 1

212.5 miles

Explanation:

Mean = (sum of the numbers) / (size of data set).

Let's call sum of miles for first 5 days A, and sum of miles for first 6 days B.

185.5 = A/5

A = 5 X 185.5 = 927.5

190 = B/6

B = 6 X 190 = 1140

miles driven on sixth day = 1140 - 927.5 = 212.5 miles