Answer: Charles practiced for 9 hours for the relay race last week.
Explanation:
Since we have given that
For every 5 hours that Eric spends practicing hurdles, he practices the javelin for 1.5 hours.
So, it means ,
For every 15 hours that spends practicing hurdles, he practices the javelin for
Now, we have also given that ,
Eric and Charles practiced javelin for the same amount of time,
It means Charles practiced javelin for 4.5 hours .
Now, we can relate that ,
For every 5 hours that Charles spends practicing for the relay race, he practices the javelin for 2.5 hours.
Let the time taken by Charles in practicing for the relay race last week be x.
If Charles practiced javelin for 4.5 hours, he will practice for relay race for
Hence, Charles practiced for 9 hours for the relay race last week.