Jordan can build a birdhouse in 2 hours. if it takes her sister 3 hours to build a birdhouse, how long will it take them to build a birdhouse together?

To find the total work of two people at different speeds, we need to find a common speed limit to both.

In this case, Jordan can build a birdhouse in 2 hours so her speed is 1/2 birdhouse per hour.

For the sister, it takes 3 hours to build a birdhouse so her speed is 1/3 birdhouse per hour.

To find what they can do in one hour:

To find how long does it take to build a birdhouse:

Set the denominators equal:

Remove the denominators and solve:

Once again set the denominators equal:

Remove the denominators and solve for x:

6/5 hours is equal to 72 minutes.