Petrolyn motor oil is a combination of natural oil and synthetic oil. it contains 5 liters of natural oil for every 6 liters of synthetic oil. if 498 liters of synthetic oil are used, how many liters of petrol oil will be made

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.