Question

7.5x+20y=900 models how many hours (x) and how many lawns mowed (y) Jon has to work in order to save $900. Give 3 combinations of hours worked and lawns mowed that result in $900.

Answer 1

`(1,\:\:44.625)`

`(2,\:\:44.25)`

`(3,\:\:43.875)`

Step-by-step explanation

We chose a value for
`x` and substitute in to the equation and solve for
`y`.

If Jon works for
`x=1` hour,

Then the equation becomes,

`7.5(1)+20y=900`

We make
`y` the subject

`7.5+20y=900`

`20y=900-7.5`

`20y=892.5`

`y=(892.5)/(20)`

`y=44.625`

If Jon works for
`x=2` hours,

Then the equation becomes,

`7.5(2)+20y=900`

We make
`y` the subject

`15+20y=900`

`20y=900-15`

`20y=885`

`y=(885)/(20)`

`y=44.25`

If Jon works for
`x=3` hours,

Then the equation becomes,

`7.5(3)+20y=900`

We make
`y` the subject

`22.5+20y=900`

`20y=900-22.5`

`20y=877.5`

`y=(877.5)/(20)`

`y=43.875`

Therefore three combinations of hours worked and lawns mowed are

`(1,44.625)`

`(2,44.25)`

`(3,43.875)`