Answer:
Step-by-step explanation:
Set this up as a ratio of proportions of petrol : oil
[tex]\frac{p}{o}[/tex] and if the ratio of the mix has to be 5p to 2 oil then:
[tex]\frac{p}{o}:\frac{5}{2}[/tex] We need to find how much oil, x, is needed to mix with 10 liters of petrol. Completing the proportion with that ratio gives us the problem in its entirety:
[tex]\frac{p}{o}:\frac{5}{2}=\frac{10}{x}[/tex] and cross multiply
5x = 20 so
x = 4 liters of oil are needed to mix with 10 liters of petrol.