Find the cost per bottle for each package and compare the results.
9-pack for $ 4.50, see solution.
Practice makes perfect
We want to determine which package costs the least per bottle. Let's start by summarizing all the information from the exercise in a table.
Package
Price
6 bottles
$3.79
9 bottles
$ 4.50
12 bottles
$6.89
We will find the unit price for each package from the table. Let's start with the package from the first row of the table. We know that a 6-pack of bottled water costs $ 3.79. We can write a rate to show this situation.
$ 3.79/6bottlesRecall that a unit rate is a rate that has been reduced to a denominator of 1 unit. In this case, the unit rate is the unit price of water per bottle. Let's find the unit rate! We can ignore the units for now to keep things simple.
We found the unit rate!
$ 3.79/6bottles ≈ $ 0.63/1bottle
As we can see, water from the first package costs $0.63 per bottle. We can find the unit rate for the other packages by following the same steps.
Package
Price
Rate
Unit Rate
6 bottles
$3.79
$ 3.79/6bottles
$ 3.79 ÷ 6/6bottles ÷ 6 ≈ $ 0.63/1bottle
9 bottles
$ 4.50
$ 4.50/9bottles
$ 4.50 ÷ 9/9bottles ÷ 9 = $ 0.50/1bottle
12 bottles
$6.89
$ 6.89/12bottles
$ 6.89 ÷ 12/12bottles ÷ 12 ≈ $ 0.57/1bottle
Remember, the unit rate is the price per bottle.
Package
Price
Unit Rate
Unit Price
6 bottles
$3.79
≈ $ 0.63/1bottle
≈ $ 0.63 per bottle
9 bottles
$ 4.50
$ 0.50/1bottle
$ 0.50per bottle
12 bottles
$6.89
≈ $ 0.57/1bottle
≈ $ 0.57 per bottle
We can see that the 9-pack costs the least per bottle.
