In 1992, Jason bought a gallon of gas for $1.20. Yesterday, he bought a gallon of gas for $2.14. What is the percentage increase of the price of a gallon of gas from 1992 to yesterday? If necessary, round to the nearest tenth of a percent.
So (2.14 - 1.2)/1.2 = 0.78333... so 78.3333 percent increase. You have to memorize the formula: Percent increase = (New percent - Old percent)/Old percent