Because m over 9 is equal to 2 over 3, m = 6. Since 9 is equal to 3 times 3, you have to multiply 2 times 3. You multiply because whatever you do to 1 number of the fraction, you do to the other.
Step-by-step explanation: you use division, or your calculator, divide $15.00 by $3.50 and you get 4.28, so you can by 4 full gallons with $1.00 left over!
