Question

Mary bought 4 gallons of milk for $11. Jill bought 2.5 gallons for $7.25.

Who had the better buy?

Answer 1

Answer: Mary

Step-by-step explanation: 11/4= $2.75 per gallon

7.25/2.5= $2.9 per gallon

Answer 2

`\boxed {\tt Mary , \$2.75/gallon}`

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.

`unit \ price =(price)/(gallons)`

Mary

Mary bought 4 gallons for $11.

`unit \ price =(price)/(gallons)`

The price is $11 and the gallons are 4.

`unit \ price =(\$11)/(4 \ gallons)`

`unit \ price =\$ 2.75 /gallon`

Jill

Jill bought 2.5 gallons for $7.25

`unit \ price =(price)/(gallons)`

The price is $7.25 and the gallons are 2.5

`unit \ price =(\$7.25)/(2.5 \gallons)`

`unit \ price =\$2.9/gallon`

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.