Question

Suppose you live near a park that has a bike trail you like to ride. The park department rent a bike with safety equipment for five dollars a day. If you provide your own safety equipment the right rental is three dollars a day. You could buy the equipment at a sports store for $28. How many times must you use the trail to justify buying your own safety equipment?

Answer 1

Equation 1 (rent): y = 5x

Equation 2 (buy): y = 3x + 28

5x = 3x + 28       substituted "y" with "5x" into Equation 2

2x = 28                subtracted 2x from both sides

x = 14                   divided both sides by 2

You will break even on the 14th time.  You will save money by renting if you go 15 times.

Answer: 15 times