One crew can seal a parking lot in 6 hours and another in 8 hours. How long will it take to seal the parking lot if the two crews work together?

Question

One crew can seal a parking lot in 6 hours and another in 8 hours. How long will it take to seal the parking lot if the two crews work together?

Answer 1

Never mind. I was wrong.

Answer 2

In one hour the fast crew does 1/6 of the job.

In one hour the slow crew does 1/8 of the job

 

In x hours the fast crew does x/6 of the job

In x hours the slow crew does x/8 of the job

 

x/6 + x/8 = 1                   1 because there is only 1 job.

8x + 6x = 48

24x = 48

x = 2

 

Working together they take 2 hours to do the job.