Step-by-step explanation:
In order to find the better buy, we must find the cheaper unit price or price per gallon. To find the price per gallon, divide the cost by the number of gallons.
Mary
Mary bought 4 gallons for $11.
The price is $11 and the gallons are 4.
Jill
Jill bought 2.5 gallons for $7.25
The price is $7.25 and the gallons are 2.5
Better buy
Mary paid $2.75 per gallon and Jill paid $2.90 per gallon. 2.75 is less than 2.90, so Mary had the better buy.
