However, I personally think this does not make sense. A leaf blower should take more gas than oil, right? For this reason, I will provide an additional answer.
If the ratio of gas to oil is 40:1, then you would multiply by 4 to get 4 oz oil and 160 oz gas.
Alternate answer:
If the ratio of oil to gas is 40:1, then you divide by 10 on both sides to get 4 oz oil and .1 oz gas.
