SOLUTION: i'm having a hard time on solving this problem: A group of workers can do a job in 8 days. After this group had worked in 3 days, another group had joined. Together they complet

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Question 478529: i'm having a hard time on solving this problem:
A group of workers can do a job in 8 days. After this group had worked in 3 days, another group had joined. Together they completed the job in three more days. How long could the second group have done the job alone?
please help me with this!
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A group of workers can do a job in 8 days.
After this group had worked in 3 days, another group had joined.
Together they completed the job in three more days.
How long could the second group have done the job alone?
:
Let x = time required by the 2nd group to do the job
Let the completed job = 1
:
From the given information, we know that the 1st group worked 6 days & the 2nd group worked 3 days
:
A typical shared work equation, each group does a fraction of the job,
the two fractions add up to 1.
:
6%2F8 + 3%2Fx = 1
multiply by 8x, results:
6x + 3(8) = 8x
24 = 8x - 6x
24 = 2x
x = 24%2F2
x = 12 days for the 2nd group to do the job
:
:
See if this adds up:
6/8 + 3/12
3/4 + 1/4 = 1
:
:
Did this method make sense to you?