What is the total number of miles akim runs over the course of 18 days?

Hello!

First you have to list the miles he ran

He started with 1.75 and increases it by 0.25 miles every day

He ran 1.75, 2, 2.25, 2.5, 2.75, 3, 3.25, 3.5, 3.75, 4, 4.25, 4.5, 4.75, 5, 5.25, 5.5, 5.75 and 6 miles

Now we add all these numbers

1.75 + 2 + 2.25 + 2.5 + 2.75 + 3 + 3.25 + 3.5 + 3.75 + 4 + 4.25 + 4.5 + 4.75 + 5 + 5.25 + 5.5 + 5.75 + 6 = 69.75

The answer is B) 69.75 mi

Hope this helps!

On the 18th day, Akim runs 1.75 + 17×0.25 = 6 miles. Then his average mileage each day over the period is (1.75 +6)/2 = 3.875 miles.

Akim's total mileage is 18×3.875 = 69.75 miles. . . . . . . matches the 2nd choice