Answer:
The oil needed is 0.51.
Explanation:
Since you know that the gas to oil ratio is 50:1 and you have to find the oil needed for 25.5L of gas, you can write the numbers in the ratio as a fraction and let's consider that x is the amount of oil needed:
Now, you have to solve this using cross multiplication:
50*x=25.5*1
50x=25.5
Finally, your have to isolate the variable x:
x=25.5/50
x=0.51
According to this, the answer is that the oil needed is 0.51.