Question

Petrolyn motor oil is a combination of natural oil and synthetic oil. It contains 7 liters of natural oil for every 4 liters of synthetic oil. In order to make 682 liters of Petrolyn oil, how many liters of natural oil are needed?

Answer 1

P ＝ N + S

N/S＝7/4

`n = (7)/(4) s`

p＝682

`682 = (7)/(4) s + s`

`682 = (11)/(4) s`