Respuesta :

He swims 20 laps per hour

Answer

Derek swims 20 laps per hour.

Explanation

If Derek swims 5 laps in 1/4 of an hour, he swims 4 times of 5 laps in an hour. This is because 4 times 1/4 is one, or an hour. 5 times 4 is 20.

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