Worker efficiency. In a study of worker efficiency at Wong

Laboratories it was found that the number of components
assembled per hour by the average worker t hours after
starting work could be modeled by the formula

N(t)=-3t+23t^2+8t

3 answers

You did not post the question: the answers you are asked to find using that formula.
Here are questions to worker question solve the problem.
a) Rewrite the formula by factoring the right-hand side
completely.
b) Use the factored version of the formula to find N(3).
c) Use the accompanying graph to estimate the time at
which the workers are most efficient.
d) Use the accompanying graph to estimate the
maximum number of components assembled per
hour during an 8-hour shift.

300
*
200

100
_*_________________*
0 1 2 3 4 5 6 7 8
The production in components per hour at t hours after starting work
= N'(t)
= d(-3t+23t^2+8t)/dt
= -3+46t+8
= 5+46t

However, I believe there is a typo in the expression of N(t) where -3t...+8t does not appear right.