Solve the Problem $$P ( t ) = - 1,840 t ^ { 2 } + 81,000 t + 10,000$$

Multiple Choice

Solve the problem.
-The population P(t) of a culture of bacteria is given by $$P ( t ) = - 1,840 t ^ { 2 } + 81,000 t + 10,000$$ where t is the time in hours since the culture was started. Determine the time at which the population is at a
Maximum. Round to the nearest hour.

A) 22 hr
B) 44 hr
C) 9 hr
D) 18 hr