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?

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".

thats not a system of equations, that is a solution