Answer:
24 minutes
Explanation:
8 * 5 = 40 ft²
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Method I: Use a proportion
x/40 = 45/75
multiply both sides by 40
x = 45/75 * 40
x = 24
24 minutes
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Method II: Use the rate
45/75 = 0.6min/ft²
40 * 0.6 = 24
24 minutes