SOLUTION: A and B can do a work in 12 days and 20 days.A works alone for 4 days and then B joins to help.in how many days will they finish the job? ans- A in 1 day = 1/12 B in 1 day

Question 948826: A and B can do a work in 12 days and 20 days.A works alone for 4 days and then B joins to help.in how many days will they finish the job?
ans- A in 1 day = 1/12
B in 1 day = 1/20
A alone works for 4 days
therefore in 4 days A'work = 4*1/20= 1/5
Remaining work 4/5
then B joins......
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
You made a mistake.
A working for 4 days would be,

So that leaves to complete.
.
.
.
So then use the rate for A and B together.

So then,

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