SOLUTION: solve. Round to the nearest tenth of necessary Mr. Jansen can shingle a roof in 10hrs, and Mr. Doyle can do it in 8 hrs. Mr. Davies has never done the job alone; but last time

Question 1034413: solve. Round to the nearest tenth of necessary

Mr. Jansen can shingle a roof in 10hrs, and Mr. Doyle can do it in 8 hrs. Mr. Davies has never done the job alone; but last time he helped with a similar job, it took the three men 3 1/3 hrs working together. How long would it take Mr. Davies alone?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates of working to get
their rate working together
Mr. Jansen's rate:
[ 1 roof ] / [ 10 hrs ]
Mr. Doyle's rate:
[ 1 roof ] / [ 8 hrs ]
The 3 men working together:
[ 1 roof ] / [ 3.5 hrs ]
----------------------------
Let time in hrs for Mr. Davies to
shingle the roof working alone

Multiply both sides by

hrs
and

-------------------------
Working alone, Mr Davies takes 16 hrs 28 min
-------------------------
check:

OK
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