Using proportions, it is found that Juan spends 15 minutes on each 5-point problem.
A proportion is a fraction of a total amount, and is solved using a rule of three.
In this problem, the amount of time is proportional to the amount of points the problem is worth. Hence, for a 5-point problem, in a 75-minute time, the time is given by:
t = 75/5 = 15 minutes.
More can be learned about proportions at https://brainly.com/question/24372153
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