Answer:
The average rate of speed is 15 miles per hour
Step-by-step explanation:
Given a bicyclist started riding at 8:00 am
Between 8:00 am and 8:14 am, that is, 14 minutes, he travelled 3.5 miles
And, between 8:14 am and 8:40 am, that is, 26 minutes, he travelled 6 miles
Total time = 14 + 26 = 40 minutes
=
![(40)/(60) hours =(2)/(3) hours](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lvqbpkysriwtx86m9zh0npqhxzvdzsdb7k.png)
Total distance travelled = 3.5 + 6.5 = 10 miles
![Speed = (Distance)/(Time)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ailgfscgsxg6gsnv86noa9ntzc9mum2vr0.png)
Substituting the values,
![\text { Speed }=(10)/((2)/(8))=10 * (3)/(2)=5 * 3=15 \text { miles per hour }](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vdsgewv4bu839iz2qmf82fb8dcdklh7igb.png)
Therefore, the average rate of speed is 15 miles per hour