## 140. Math Puzzle $1 / 77$

In a 20-liter canister, there is a fuel mixture with a mixing ratio of gasoline to oil $=33.33: 1$. How many liters of oil are in the canister?
For a fuel mixture ratio of 33.33:1, 1 liter of oil is added to 33.33 liters of gasoline - this results in 34.33 liters of mixture. If 34.33 liters of fuel contain 1 liter of oil, then in a 20-liter canister,

$$
\frac{1}{34.33} \cdot 20 \mathrm{l}=0.582 \mathrm{l} \text { of oil }
$$