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%.