SOLUTION: Bob the bricklayer can complete a stone wall in 8 hours. Butch the bricklayer can finish the wall in 5 hours. If the two work together on the wall, how long will it take them to co

Algebra ->  Equations -> SOLUTION: Bob the bricklayer can complete a stone wall in 8 hours. Butch the bricklayer can finish the wall in 5 hours. If the two work together on the wall, how long will it take them to co      Log On


   

Question 123221: Bob the bricklayer can complete a stone wall in 8 hours. Butch the bricklayer can finish the wall in 5 hours. If the two work together on the wall, how long will it take them to complete it?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
You want to add their rates of working to get their
combined rate. In words:
(1 wall / 8 hours) + (1 wall / 5 hours) = 1 wall / x hours
1%2F8+%2B+1%2F5+=+1%2Fx
multiply both sides by 40
5+%2B+8+=+40%2Fx
13+=+40%2Fx
x+=+40%2F13
x+=+3.076hrs
.077 hrs = .077%2A60+=+4.62 minutes
So, working together, they can finish in about 3 hrs 4.6 minutes