The price of gasoline is $2.27 per gallon and decreases at the rate of $0.03 every two months. oil costs $0.45 per gallon and increases at a rate of $0.05 every six months. how many years will it take for them to be equal in price?

a) 6.5
b)6
c)7
d)5.5

this is on an asvab pretest, i know the answer is 6.5, i dont know how to get to that answer tho and really want to understand how. you.