roads leading to an arena can together handle 3,500 vehicles/hour of arena - only traffic, at what time…

roads leading to an arena can together handle 3,500 vehicles/hour of arena - only traffic, at what time should the roads be closed to other vehicles to ensure that the projected 14,000 vehicles can get to the arena for the 7 p.m. start? 3 p.m. 4 p.m. 5 p.m. 6 p.m.
Answer
Answer:
A. 3 p.m.
Explanation:
Step1: Calculate time needed
We know the rate is 3500 vehicles/hour and the number of vehicles is 14000. Using the formula $t=\frac{n}{r}$ (where $t$ is time, $n$ is number of vehicles, $r$ is rate), we have $t = \frac{14000}{3500}=4$ hours.
Step2: Determine closing - time
The event starts at 7 p.m. Subtracting the 4 - hour time needed for all vehicles to get to the arena, 7 - 4 = 3 p.m. So the roads should be closed at 3 p.m.