John traveled 80% of the way from yellow-town to green-fields by train at an average speed of 80 miles per hour. the rest of the way john traveled by car at an average speed of v miles per hour. if the average speed for the entire trip was 60 miles per hour, what is v in miles per hour?

Question

Maren Krause

Mathematics

16 June, 07:06

John traveled 80% of the way from yellow-town to green-fields by train at an average speed of 80 miles per hour. the rest of the way john traveled by car at an average speed of v miles per hour. if the average speed for the entire trip was 60 miles per hour, what is v in miles per hour?

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Answers (1)

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Seth Terry · Answer 1

Pick 100 km for D ...

This would yield T=100 minutes

Using the question stem we calculate 80 km were traveled in 1h (or 60 minutes) ...

This leaves us with 40 minutes (2/3 of an hour) to travel 20km ...

R*T=D

R*2/3=20

R=30

Answer A ...