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.

Correct option is D

Given:
The bicyclist travels 20 miles in 2 h and 30 min and 10 miles in 1 h 15 min.
Formula Used:
​$$\text{Average Speed} = \dfrac{\text{Total Distance}}{\text{Total Time}}$$​​
Solution:
Total distance = 20 miles + 10 miles = 30 miles.
Total time = 2.5 hours + 1.25 hours = 3.75 hours.
$$\text{Average Speed} = \dfrac{\text{Total Distance}}{\text{Total Time}}$$​= $$\dfrac{30 \ \text{miles}}{3.75 \ \text{hours}} = 8 \ \text{miles/hour}$$​​
Therefore, the average speed of the bicyclist is 8 miles per hour