Find the time when the bacteria count reaches 23901.

Question

The number of bacteria in a refrigerated food product is given by , , where  is the temperature of the food.

When the food is removed from the refrigerator, the temperature is given by , where  is the time in hours.

Find the composite function :

N(T(t))=

Find the time when the bacteria count reaches 23901.

Time Needed =

Answer 1

1. Find the composite function N(T(t)) by substituting (3t + 1.2) with T in N(T)= 25T^2 − 128T + 70.
2. Let N(T(t)) = 23901, you will get an quadratic equation. Solve the equation to get the time.