In 1987 the average price of gasoline was $0.94. Today the price of gas is about $3.00. What is the percent increase from 1987 to today? (explain the problem please)

Hello there! So we are looking for the percent increase of the gas of the present day, compared to 1987. To find the percent increase, we can write and solve a proportion. We would write the proportion as change/original = x/100. Change is the distance between the two numbers and original is the previous number, in this case, 0.94. Subtract 0.94 from 3 to get 2.06. We have the change. Set it up like this:

2.06/0.94 = x/100

Let's cross multiply the values diagonally. 100 * 2.06 is 206. 0.94 * x is 0.94x. That makes 206 = 0.94x. Divide each side by 0.94 to isolate the x. 0.94x/0.94 cancels out. 206/0.94 is 219.1489 and other numbers behind it or 219 when rounded to the nearest whole number. There. The percent of increase is approx. 219%.