Answer: Shannon has better gas mileage.
Step-by-step explanation: To find who has better gas mileage, you have to find the unit rate of both numbers. The equation for unit rate is a/b = c/1. We can replace the letters with numbers and have...
728 miles/20 gallons = c miles/1 gallon and
487.5 miles/15 gallons = c miles/1 gallon
you are going to solve for c, and in the first equation, c = 36.4 miles and in the second equation, c = 32.5 miles. because 36.4 is greater than 32.5, Shannon has better gas mileage.