CPM Homework Help : PC Problem 7-126

Excluding breaks, it took Chun a total of $10$ hours to bike to a cousin’s home and return. On the way, Chun biked alone and averaged $15$ mph. On the way back, with his cousin, he averaged $10$ mph. How many miles was it to his cousin’s home?

Hint:

(rate)(time) $=$ distance

Step:

Since the distance to the house is the same as the distance from the house:

$\left(15 \frac{\text{miles}}{\text{hour}}\right)(t\text{ hours})=\left ( 10 \frac{\text{miles}}{\text{hour}}\right )(10 \text{ hours }-t\text{ hours})$

where $t =$ time spent traveling to the house