In this problem, we use the method of ratio and proportion. This technique works by using the concept that there is a fixed ratio of compositions within a mixture. Speaking generally, there is a fixed ratio of the parts of the whole. So, all we have to do is equate both ratios.
5 L natural oil/ 6 L synthetic oil = x L natural oil/498 L synthetic oil
x = 415 L natural oil
So, if petrol oil contains 498 L synthetic oil, it has a corresponding amount of 415 natural oil. Adding these two would be the total volume of the petrol oil. That would be 415+498 = 913 L petrol oil.
