At the moment a hot cake is put in a cooler, the difference between the cake's and the cooler's temperatures is 50\degree50°50, degree Celsius. This causes the cake to cool and the temperature difference loses \dfrac15
5
1

start fraction, 1, divided by, 5, end fraction of its value every minute.
Write a function that gives the temperature difference in degrees Celsius, D(t)D(t)D, left parenthesis, t, right parenthesis, ttt minutes after the cake was put in the cooler.
D(t)=D(t)=D, left parenthesis, t, right parenthesis, equals