A certain car increased its average
speed by 5 miles per hour in each
successive 5-minute interval after the
first interval. If in the first 5-minute
interval its average speed was 20
miles per hour, how many miles did
the car travel in the third 5-minute
interval?
(A) 1.0
(B) 1.5
(C) 2.0
(D) 2.5
(E) 3.0