Answer:
(a) 25 degrees
(b) -11 degrees
(c) 38 degrees
Explanation:
The temperature function is:

(a) The average value for a temperature is:

In this particular case, the average temperature is:


The average temperature is 25 degrees.
(b) The expression is a parabola that is concave down, therefore there are no local minimums, which means that the minimum temperature will be at one of the extremities of the interval:

The minimum temperature is -11 degrees.
(c) The maximum temperature will occur at the point for which the derivate of the temperature function is zero:

At t = 2, the temperature is:

The maximum temperature is 38 degrees.