The cost, C, to produce b baseball bats per day is modeled by the function. What number of bats should be produced to keep costs at a minimum

Answer:
60
Step-by-step explanation:
Take the function's first derivative
C'(b) = 0.12b -7.2
7.2 = 0.12b
b = 7.2 / 0.12
b = 60
Second derivative test
C''(b) = 0.12 (+).
for all values of b, the graph will be concave downwards, therefore is value is confirmed to be a minimum