Question

At the store, a package of four AA batteries costs $3.92. A package of eight of the same batteries

cost $7.60
a.) Which package is the better buy? Justify your answer.
b.) If you needed to purchase 16 batteries, how much money would you save by purchasing the
package of batteries that is a better buy? Show your work and explain your answer.
​

Answer 1

Part a) A package of eight AA batteries is the better buy

Part b)
`\$0.48`

Explanation:

Part a) Which package is the better buy?

To find the better buy, calculate the unit rate

A package of four AA batteries costs $3.92

so

The unit rate is equal to

`(\$3.92)/(4)=0.98(\$)/(battery)`

A package of eight AA batteries costs $7.60

so

The unit rate is equal to

`(\$7.60)/(8)=0.95(\$)/(battery)`

`0.95(\$)/(battery)< 0.98(\$)/(battery)`

therefore

A package of eight AA batteries is the better buy

Part b) If you needed to purchase 16 batteries, how much money would you save by purchasing the package of batteries that is a better buy?

If you buy two package of eight batteries (16 batteries)

then

The cost would be ------>
`\$7.60(2)=\$15.20`

If you buy four package of four batteries (16 batteries)

then

The cost would be ----->
`\$3.92(4)=\$15.68`

therefore

Purchasing the package of batteries that is a better buy

you save

`\$15.68-\$15.20`

`\$0.48`