Answer:
50.0 degrees
Step-by-step explanation:
The temperature of the coffee for any given instant "t", in minutes, can be described by the following expression:
[tex]T = R+(I-R)*(1-r)^t[/tex]
Where 'R' is the room temperature, 'I' is the initial temperature of the coffee, and 'r' is the cooling rate. Applying the given values, for t =28 minutes:
[tex]T = 20+(74.4-20)*(1-0.021)^t\\T= 50.0[/tex]
The temperature of the coffee will be 50 degrees 28.0 minutes from now