Answer:
62.5 tons.
Explanation:
Let x be the tons of petroleum.
We have been given that we can get 30% of paraffin from some petroleum.
To find the the amount of petroleum we need to figure out x such that 30% of x is 18.75.
We can represent this information in an equation as:

Let us solve for x.

Let us divide both sides of our equation by 0.30.


Therefore, we need 62.5 tons of petroleum to get 18.75 tons of paraffin.