Question

Difficulty: EasyUnit Conversions in Motion Problems

A cyclist is riding on a paved trail at a constant speed of 15 miles per hour15 \text{ miles per hour}. At this rate, how many miles will the cyclist travel in 40 minutes40 \text{ minutes}?

Answer: 10 miles

Answer

10
The distance is found by matching the time units to the speed units. First, convert 40 minutes40 \text{ minutes} into 23 hours\frac{2}{3} \text{ hours}. Then, multiply the speed (15 mph15 \text{ mph}) by the time (23 hours\frac{2}{3} \text{ hours}) to get exactly 10 miles.

Step-by-Step Solution

1
Convert the travel time from minutes to hours.
40 minutes=4060 hours=23 hours40 \text{ minutes} = \frac{40}{60} \text{ hours} = \frac{2}{3} \text{ hours}
The speed is given in miles per hour, so the time must be converted to hours before using it in the distance formula.
2
Calculate the total distance traveled.
15×23=10 miles15 \times \frac{2}{3} = 10 \text{ miles}
Distance is equal to the rate (speed) multiplied by the time (d=r×td = r \times t).

Key Concept

Unit conversions for time in rate problems
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