Question

You fill your car with 15 gallons of gas at a cost of $45. Using fractional notation, how do you write a proportion that shows how much 5 gallons of gas will cost? Use x to represent the unknown cost.(1 point)

15/x=45/5

15/45=5/x

15/45=x/5


15 : 45 :: x : 5

Answer 1

15/45 = 5/x

( Cross-multiply: 15x = 45·5 → x = 225/15 = 15, so 5 gallons costs $15.)