Answer:
1.4 hours have elapsed when the father and his son are 20.16 miles apart
Explanation:
The son runs at a speed of 8.1 mph.
The father runs at a speed of 6.3 mph.
They run in opposite directions, so per hour, their distance increases at the rate of 8.1 + 6.3 = 14.4 mph.
How many hours will have elapsed when the father and his son are 20.16 miles apart?
Rule of 3.
1 h - 14.4 miles
x h - 20.16 miles
![14.4x = 20.16](https://img.qammunity.org/2021/formulas/mathematics/college/rauq3f30hs8u231d0hcxdc2dm1jfwmmlzo.png)
![x = (20.16)/(14.4)](https://img.qammunity.org/2021/formulas/mathematics/college/49getr9emvk4jxqwkyq220ltbfnbq1a1a5.png)
![x = 1.4](https://img.qammunity.org/2021/formulas/mathematics/college/9wdejvkahpgvknozxq2wlyx1abugt7obmc.png)
1.4 hours have elapsed when the father and his son are 20.16 miles apart