A cup of coffee cools according to the function T = 70(0.80)* + 20, where x is the time in

minutes and T is the temperature in degree Celsius.
What is the temperature after 10 minutes?

7.5
20
27.5
76

1 answer

27.5

Plugging in x = 10 into the function T = 70(0.80)^10 + 20 gives us T = 70(0.1073741824) + 20 = 27.5.