A bicyclist travels 20 miles in 2 h and 30 min and 10 miles in 1 h 15 min. Find the average speed in miles per hour.
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e. 8.
Average speed = Total distance/Total time
Total distance = 20 + 10 = 30 miles
2 hour and 30 min = 2 + 1/2 = 5/2 and,
1 hour and 15 min = 1 + 1/4 = 5/4
Average speed = 30/(5/2 + 5/4)
⇒ 30/(15/4) = 120/15 = 8