A petroleum laboratory technician is working at a petroleum storage depot in the oil-analysis laboratory. The lab tech is running tests on a sample from a 45-gallon oil-solvent mixture that contains 18 gallons of oil. What is the ratio of the number of gallons of oil to the number of gallons of solvent? a.) 2/5 b.) 3/5 c.)2/3 d.)3/2 3.)5/3