Problema Solution

two workers A & B together could finish a work in 8 days. they work together for 6 days and A left. remaining work was finished by B alone in 6 days. how many days individually each would have taken to finish the work?

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let


a = the time in days that A needs to finish the job alone


the rate of A per day is: 1/a work/day


b = the time in days that B needs to finish the job alone


the rate of B per day is: 1/b work/day


two workers A & B together could finish a work in 8 days means that hey together rate per day is: 1/8 work/day


thus we can write:


1/a + 1/b = 1/8


they work together for 6 days and A left


this means 6/8 of the job was done


what is remaining is 1 - 6/8 = 2/8 = 1/4 of the job


B finished the remaining 1/4 of the job alone in 6 days, this means:


6(1/b) = 1/4


by solving we find:


b = 24 days


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B needs 24 days to finish the job alone.


Using 1/a + 1/b = 1/8 and plugging b = 24 we find a:


1/a + 1/24 = 1/8


by solving we find:


a = 12 days


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A needs 12 days to finish the job alone.