15:1.79 or 12:1.49 make fractions 15/1.79 12/1.49 find LCM of 12 and 15 find factors of 12 and 15 12=2 times 2 times 3 15=3 times 5 LCM=2 times 2 times 3 times 5=60 multiply 15/1.79 by 4/4=60/7.16 multiply 12/1.49 by 5/5=60/7.45 7.45>7.16 so therefor 12oz for 1.49 is better