Question

Frances can complete 91 oil changes in 7 days.how many oil changes complete in 11 days

Answer 1

let oil change be x
91 / 7 = x / 11
(91 * 11) / 7 = x
13 * 11 = x
143 = x Ans

Answer 2

`143\ oil\ changes`

Explanation:

we know that

Frances can complete
`91` oil changes in
`7` days

so

by proportion

Find how many oil changes complete in
`11` days

`(91)/(7)(oil\ changes)/(days) =(x)/(11)(oil\ changes)/(days)\\ \\x=11*91/7\\ \\x=143\ oil\ changes`