Question

Rayna and Desi are building a fence together. It takes Rayna $3$ hours to make $10$ feet of fence line. It takes Desi $1$ hour to make $2$ feet of fence line. How many hours will it take them to build $80$ feet of fence line together?

Answer 1

Answer: Let's call the number of hours it takes for Rayna and Desi to build the fence together as "h". During this time, Rayna will build 10h feet of fence line, and Desi will build 2h feet of fence line.

Together, they will build 10h + 2h = 12h feet of fence line in h hours.

To build 80 feet of fence line, they will need h hours such that:

12h = 80

So,

h = 80 / 12 = 6.67 hours

So it will take Rayna and Desi 6.67 hours to build 80 feet of fence line together.

Explanation: