Leo needs to drive from Boston to Chicago. He planned to drive for 20 hours at an average speed of 50 mph. But drove 60 mph for the first 5 hours. During the remaining part of the trip, his average speed was 50 mph, how much earlier did he arrive in Chicago than he originally planned?

Question

Mathematics

Alivia

21 June, 03:45

Leo needs to drive from Boston to Chicago. He planned to drive for 20 hours at an average speed of 50 mph. But drove 60 mph for the first 5 hours. During the remaining part of the trip, his average speed was 50 mph, how much earlier did he arrive in Chicago than he originally planned?

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Answers (1)

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Agustin Boyd · Answer 1

He arrived 1 hour earlier.

The formula for distance in this case is

d=rt, where d is distance, r is rate (speed) and t is time.

The first leg of his trip, he traveled at 60 mph for 5 hours:

d = 60 (5) = 300

He traveled 300 miles during the first part of his trip.

He had originally planned to travel 50 mph for 20 hours:

d = rt = 50 (20) = 1000

His entire trip is 1000 miles.

The second part of the trip is then represented by

1000-300 = 50t

700 = 50t

Divide both sides by 50:

700/50 = 50t/50

14 = t

He traveled 5 hours for the first part and 14 hours the second part, for a total of 19 hours.

This is 20-19 = 1 hour earlier than he'd planned.