Eric and Charles are on their high school track and field team. Eric is participating in hurdles and the javelin. For every 5 hours that Eric spends practicing hurdles, he practices the javelin for 1.5 hours. Charles is participating in a relay race and the javelin. For every 5 hours that Charles spends practicing for the relay race, he practices the javelin for 2.5 hours.
If Eric practiced hurdles for 15 hours last week, and Eric and Charles practiced javelin for the same amount of time, then how long did Charles practice for the relay race last week?
A.
18 hours
B.
9 hours
C.
7.5 hours
D.
4.5 hours
If Eric practiced hurdles for 15 hours last week, he would have practiced the javelin for 15 hours / 5 hours per hurdle practice * 1.5 hours per javelin practice = 4.5 hours.
Since Eric and Charles practiced javelin for the same amount of time, Charles also practiced the javelin for 4.5 hours.
For Charles to practice the javelin for 4.5 hours, he would have practiced the relay race for 5 hours / 2.5 hours per javelin practice = 2 hours.
Therefore, Charles practiced for the relay race for 2 hours.
The correct answer is D. 4.5 hours.