Answer:
105 °F
Explanation:
Add 10 °F to the temperature for each of the 3 hours:
75 °F + 10 °F + 10 °F + 10 °F = 105 °F
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Of course, multiplication was invented to make repeated addition easier. Multiplying the increase each hour by the number of hours gives the total increase:
75 °F + (3 h)(10 °F/h) = 75 °F +30 °F = 105 °F
The temperature of the hot tub after 3 hours will be 105 °F.