SOLUTION: two welders who work at the same rate are welding the girders of a building. after they work together for 10 h, one of the welders quits. the second welder requires 20 more hours t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: two welders who work at the same rate are welding the girders of a building. after they work together for 10 h, one of the welders quits. the second welder requires 20 more hours t      Log On


   

Question 446856: two welders who work at the same rate are welding the girders of a building. after they work together for 10 h, one of the welders quits. the second welder requires 20 more hours to complete the welds. find the time it would have taken one of the welders, working alone, to complete the welds.
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
10%281%2Fx+%2B+1%2Fx%29+%2B+20%2Fx+=+1
==> 10%2A%282%2Fx%29+%2B+20%2Fx+=+1
==> 20%2Fx+%2B+20%2Fx+=+1
==> 40%2Fx+=+1
==> x = 40 hours, the time it would take either one of them to finish the job alone.