A coffee is sitting on Mr. Hunt's desk cooling. It cools according to the function T=70(0.80)^x+20, where x is the time in minutes and T is the temperature in degree Celsius.

90 degrees

Step-by-step explanation:

Complete question

A coffee is sitting on Mr. Hunt's desk cooling. It cools according to the function T=70(0.80)^x+20, where x is the time in minutes and T is the temperature in degree Celsius. WHAT IS THE INITIAL temperature of the coffee

The initial temperature occurs at x = 0

Substitute x = 0 into the expression;

T=70(0.80)^x+20

T =70(0.80)^0+20

Since any value raise to power of zero is 1, hence;

T = 70(1)+20

T = 70+20

T = 90 degree Celsius

Hence the initial temperature of the coffee is 90 degrees

the answer is 13 cm