Curtis rides his bike 9 miles one way then turns around and rides back. On the return trip, his speed is increased 20% because the wind is at his back. Let s be his speed in miles per hour riding against the wind. What is an expression that represents his total time in hours riding there and back?

Question

Mathematics

Oprah

3 August, 18:02

Curtis rides his bike 9 miles one way then turns around and rides back. On the return trip, his speed is increased 20% because the wind is at his back. Let s be his speed in miles per hour riding against the wind. What is an expression that represents his total time in hours riding there and back?

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Quinn Manning · Answer 1

The expression that represents the total time of his route is "time = 16.5/s".

Step-by-step explanation:

Curti's ride has two parts, the first one which was made at a speed of "s" and the second one where his speed was 20% higher, therefore "1.2s". The total time to complete this course is the sum of the times for each part, since the average speed is given by:

time = distance/speed

Then the total time for the track is:

time = 9/s + 9 / (1.2s)

Using LMC:

time = (1.2*9 + 9) / 1.2s = (10.8 + 9) / 1.2s = 19.8 / (1.2s) = 16.5/s

The expression that represents the total time of his route is "time = 16.5/s".