SOLUTION: Mary can roof their house in 4 days working alone, her husband can roof their house in 6 days working alone. If they work together how long will it take to roof the house?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Mary can roof their house in 4 days working alone, her husband can roof their house in 6 days working alone. If they work together how long will it take to roof the house?      Log On


   

Question 1154119: Mary can roof their house in 4 days working alone, her husband can roof their house in 6 days working alone. If they work together how long will it take to roof the house?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+1%2F4+ is Mary's rate: [ 1 job ] / [ 4 days ]
+1%2F6+ is husband's rate: [ 1 job ] / [ 6 days ]
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Let +t+ = time in days for job to get done
with them working together
Add their rates of working
+1%2F4+%2B+1%2F6+=+1%2Ft+
Multiply both sides by +12t+
+3t+%2B+2t+=+12+
+5t+=+12+
+t+=+2.4+ days
They get it done in 2.4 days
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check:
+.25+%2B+.1667+=+1%2F2.4+
+.41667+=+.41667+
OK