Answer:
David exercises 100 minutes each day.
Explanation:
1. Let's review the information given to us to answer the question correctly:
David uses the treadmill 40 minutes each day = 40% of his exercise time
2. How many minutes does he exercise each day?
Let's use the Direct Rule of Three to answer this question:
Minutes Percentage
40 40
x 100
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40 * x = 40 * 100
40x = 4,000
x = 4,000/40
x = 100
David exercises 100 minutes each day.