Question

A gas station offers two ways to pay for oil changes. Plan 1: Pay $30 per oil change. y = 30x Plan 2: Pay $60 for the first oil change and $15 for every oil change after the first. y = 15x + 60 At how many oil changes will the cost for both plans be equal?

Answer 1

It will take 4 oil changes

y = 30X

120=30(4)


y= 15X + 60

y= 15(4) + 60

y = 60 + 60

y= 120

Answer 2

For plan 1 we have the following equation:
 $y = 30x$
 For plan 2 we have the following equation:
 $y = 15x + 60$
 The variables are defined as:
 x: number of oil change
 y: total cost
 Equating the cost of both plans we have:
 $30x = 15x + 60$
 From here, we clear the value of x.
 We have then:
 $30x - 15x = 60 15x = 60 x = 60/15 x = 4$
 Answer:
 The cost for both plans will be equal at 4 oil changes