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if jonah completes a trip of 240 miles at the rate of 30 mph, at what rate would he have to travel on the return trip in order to average 40 mph for the round trip?

1 Answer

5 votes

Answer:

60 mph

Explanation:

Each way of the trip is 240 miles.

The round trip is 2 × 240 miles = 480 miles

The first half of the trip, 240 miles, was made at a speed of 30 mph.

s = d/t

st = d

t = d/s

t = 240 miles / 30 mph = 8 hours

The first part of the trip took 8 hours.

The entire round trip is 240 miles × 2 = 480 miles

The speed for the entire trip is 40 mph.

480 miles / 40 mph = 12 hours

12 hours - 8 hours = 4 hours

The return trip takes 4 hours.

The return trip is 240 miles.

s = d/t = 240 miles / 4 hours

s = 60 mph

Answer: 60 mph

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