Suppose that in a certain biology lab experiment, the number of bacteria is related to the temperature T of the environment by the function $N ( T ) = - 2 T ^ { 2 } + 240 T - 5,100 ( 40 \leq t \leq 90 )$ Here, N(T) represents the number of bacteria present when the temperature is T degrees Fahrenheit. Also, suppose that t hr after the experiment begins, the temperature is given by $T ( t ) = 10 t + 40 ( 0 \leq t \leq 5 )$ How many bacteria are present when t = 5 hr?
A) 300
B) 900
C) 1,200
D) 400
E) 600

Question

Quizplus · Accepted Answer

When t = 5 hr, the temperature is T(5) = 10(5) + 40 = 90 degrees Fahrenheit. So, the number of bacteria present is N(90) = -2(90)^2 + 240(90) - 5,100 = 300.

Suppose That in a Certain Biology Lab Experiment, the Number N(T)=−2T2+240T−5,100(40≤t≤90)N ( T ) = - 2 T ^ { 2 } + 240 T - 5,100 ( 40 \leq t \leq 90 )N(T)=−2T2+240T−5,100(40≤t≤90)

Suppose That in a Certain Biology Lab Experiment, the Number $N ( T ) = - 2 T ^ { 2 } + 240 T - 5,100 ( 40 \leq t \leq 90 )$