Thread: Highway Work ( frustrated with this )

In checking records, a contractor finds that a crew A can pave a certain lenght of highway in 9hr, while crew B can do the same job in 12 hr. How long would it take if they worked together ?

Hello, diehardmath4!

Crew A can pave a certain length of highway in 9 hours,
while crew B can do the same job in 12 hours.
How long would it take if they worked together?

Crew A can do the job in 9 hours.
. . In one hour, it can do of the job.
. . In hours, it can do of the job.

Crew B can do the job is 12 hours.
. . In one hour, it can do of the job.
. . In hours, it can do of the job.

Working together for hours, they can do: . of the job.

But in hours, we expect them to complete the job (1 job).


There is our equation: .

Now solve for . . .

THANK YOU THANK YOU THANKS YOUR THE BEST !!!