Question

The traffic flow rate (cars per hour) across an intersection is

r
(
t
)
=
300
+
600
t
−
90
t
2
, where
t
is in hours, and
t
=0 is 6am. How many cars pass through the intersection between 6 am and 9 am?

Answer 1

990 cars

Explanation:

Find how many cars pass through at 6am, t=0:

r(0)= 300+600(0)-90(0²) = 300

Find how many cars pass through at 9am, t=3:

r(3)= 300+600(3)-900(3²)=300+1800-810=1290

Find the difference (how many cars pass between 6am and 9am): 1290-300=990