Question

Moe and Joe take a car trip. Moe drives at an average speed of 42 mph for the first hour and then they stop for gas for 10 minutes. After filling gas, Joe drives at an average speed of 31 mph for 40 minutes, and then the traffic clears and he gets to drive at an average speed of 60 mph for half hour. Find the average speed of the car on this trip.

Answer 1

39.77 m/s

Explanation:

We are given that

Average speed of Moe for first hour=42 mph

They stop car for gas for 10 minutes

Average speed of Joe for 40 minutes=31 mph

After traffic clear

Average speed of Joe fro half hour=60 mph

We have to find the average speed of car on his trip.

1 hour=60 minute

Total time =60+10+40+30=140 minutes

Time=
`(140)/(60)=2.33 hours`

We have to find total distance

Distance covered when average speed 42 mph=
`speed* time=42\time 1=42 mi`

Distance covered when average speed 31 mph=
`31* (40)/(60)=20.67 mi`

Distance covered when average speed 60 mph=
`60* (30)/(60)=30 mi`

Total distance=42+20.67+30=92.67 mi

Average speed =
`(distance)/(time)=(92.67)/(2.33)=39.77 m/s`

Hence, average speed on this trip=39.77 m/s