Question

use unit rates to determine the better buy and provide the unit price for your answer. round your answer to the nearest hundredth, if necessary. $18.41 for 40 AA batteries $11.45 for 24 AA batteries

Answer 1

To answer this question, we need to remember that a rate compares two different kinds of units. In this case, we have money and batteries. The unit rate, in this case, will be the price per battery (a unit rate ---> the price per one battery).

To do that, we need to divide the amount of money by the number of batteries in each case, and then compare the price per battery which is less.

Then, we have:

1. The unit rate for $18.41 for 40 AA batteries:

`\frac{18.41\text{dollars}}{40\text{batteries}}=0.46025\frac{\text{dollars}}{battery}`

If we round the value to the nearest hundredth (two decimal places), we have:

`0.46(dollars)/(battery)`

That is 0.46 dollars per battery.

2. The unit rate for $11.45 for 24 AA batteries is:

`(11.45)/(24)=0.477083333333(dollars)/(battery)`

If we round the value to the nearest hundredth, we have:

`0.48(dollars)/(battery)`

That is 0.48 dollars per battery.

As we can see, the better buy would be the one with $0.46 per battery (unit price) (that is, spending $18.41 for 40 AA batteries) since the cost per battery is less than spending $11.45 for 24 AA batteries because the price per battery is $0.48.

In summary, we need to select the option:

$18.41 for 40 AA batteries, and then we need to write 0.46 (that is, $0.46 per battery).