Question

A gallon of gas cost 30 cents in 1960 and 70 cents in 1977. What was the percent increase?

Answer 1

70-30=40
\[\frac{30}{40}=\frac{x}{100}\]30*100=40*x
3000=40x
x = 3000/40
x=75 percent

Answer 2

40/30=x/100
4000=30x
x=133.33

Answer 3

30/40*100%=appr. 130%