Twelve cubic inches of soda are left in a can that holds 20 cubic inches. What percent of the soda has been drunk? What percent of the soda is left in the can?

In these situations I always see if the bottom number can be multiplied by any number to get to 100. In this case 20 can be multiplied by 5 to get 100. Then all you do if that works is multiply the top number by the same number. So 12 * 5 = 60.

60/100 = 60%