A certain car increased its average speed by 3 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? Select.
A) 1.0 B) 1.5 C) 2.0 D) 2.5 E) 3.0
In the third time interval the average speed of the car was 20+3+5= 
<gadget id="calculator">20+3+5</gadget>
<output>28</output>
28 miles per hour;   In 5 minutes (1/12 hour) at that speed car would travel 28*1/12=2 miles.   Answer: 2.0.
<result>C</result>
A certain car increased its average speed by 3 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?