Alex and Carmen both sell items at craft fairs. Alex earns $36 for 3 birdhouses, and Carmen earns $75 for 5 scarves. What is the unit rate that each person earns for their craft? How many birdhouses will Alex need to sell in order to make as much as Carmen does when she sells 12 scarves? How do you know?

To be able to find the unit rate that each person earns for their craft, you have to divide the amount each person earns by the number of units:

Alex: $36/3=$12 per unit

Carmen: $75/5=$15 per unit

To find the amount of birdhouses that Alex will need to sell in order to make as much as Carmen does when she sells 12 scarves, first you have to determine the amount that Carmen earns when she sells 12 scarves:

$15*12=$180

Now, you need to divide $180 by the price per unit Alex earns to find the amount of birdhouses that he needs to sell:

$180/$12=15

This means that Alex needs to sell 15 birdhouses to make as much as Carmen does when she sells 12 scarves