SOLUTION: Doy and his son can do a job in 4 1/2 days. After that they have worked for 3 days, Doy got sick and his son finished the work in 6 more days. How many days are required for each o

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Doy and his son can do a job in 4 1/2 days. After that they have worked for 3 days, Doy got sick and his son finished the work in 6 more days. How many days are required for each o      Log On


   



Question 97176: Doy and his son can do a job in 4 1/2 days. After that they have worked for 3 days, Doy got sick and his son finished the work in 6 more days. How many days are required for each of them to do the work?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Doy and his son can do a job in 4 1/2 days. After that they have worked for 3 days, Doy got sick and his son finished the work in 6 more days. How many days are required for each of them to do the work?
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Let the completed job = 1
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Let S = sons time alone
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Let D = Doy's time alone
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Working together for 3 days they would have completed 3%2F4.5 of the job
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The boy worked alone for 6 days so he completed 6%2FS of the job
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Find S
3%2F4.5 + 6%2FS = 1
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Multiply equation by 4.5S to get rid of the denominators, resulting in:
3s + 4.5(6) = 4.5s
3s + 27 = 4.5s
27 = 4.5s - 3s
1.5s = 27
s = 17/1.5
s = 18 days to complete the job, the son working alone
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Find the time required by Doy working alone, using the "working together: equation:
4.5%2FD + 4.5%2F18 = 1
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Multiply equation by 18D to get rid of the denominators, results:
4.5(18) + 4.5D = 18D
81 + 4.5D = 18D
81 = 18D - 4.5D
13.5D = 81
D = 81/13.5
D = 6 days to complete the job, Doy working alone
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