Newton's law of cooling relates the rate at which a body cools to the difference in temperature between the body and the environment into which it is introduced. The formula is

F(t)=T0+Cbt,

where F(t) is the temperature of the body at time t,

T0

is the constant temperature of the environment into which the body is introduced, and C and b are constants. Use Newton's law of cooling to solve the problem below.A cup of coffee has cooled from

98

to

50

after

12

minutes in a room at

25.

How long will it take to cool to

30?