1 ) Billy walks 15 miles every day to soccer practice and he had 5 practices last week.
We know that, 1 mile = 1760 yards
So, 15 miles = (15× 1760) yards = 26400 yards
Thus the total distance walked in 5 practices will be:
![(26400*5)yards = 132000 yards](https://img.qammunity.org/2019/formulas/mathematics/college/5mjcw1s3rb82gomyqfy6ei9f7l76ie5uu5.png)
2) Mark's current age is
years
So, his age was in 10 years ago
![=(t-10)years](https://img.qammunity.org/2019/formulas/mathematics/college/3lfwamvwk19sbspgqpxt060kad0fh6by9p.png)
Given that, his current age is 3 times his age 10 years ago.
So, the equation to represent this situation will be :
![t= 3(t-10)](https://img.qammunity.org/2019/formulas/mathematics/college/gz6j3tp37idm3hsax35al79y9yhtz8gx3q.png)