A alone can finish a piece of work in 6 days, while B can finish the same in 12 days. They start working together and A quits after 2 days. Then, B works alone for 3 days and after 3 days A is called back and he finishes the remaining work alone. If they are paid $1008 for the work, find the amount that each one gets assuming that the amount is distributed in the ratio of the amount of work that they do.
(A) $588, $420
(B) $654, $350
(C) $672, $338
(D) $675, $330
(E) $679, $330
IMO A
the amount is distributed in the ratio of the amount of work that they do
to get the amount of work done = We need to find the number of days they (A and B) are working and multiply it with the rate of their work
Number of Days A worked for at First =2
Number of Days B worked for at First = 2+3 =5
Work done by A+B in the first 2 days when they were working together = (1/6+1/12)*2 = 1/2
Work left to do after first 2 days = 1/2
Work done by B alone in the next 3 days = 3*(1/12) = 1/4
Work left to do after 5th Day when A is called back to work alone = 1/4
Time taken by A to finish 1/4 of the work is = (1/4)/(1/6) = 1.5 Days
so 1.5 days A is working alone after the 5th day of Work
lets make it into a table :
_______________________
Days : Work Done by
______________________
Day 1-2 : A+B
Day 3-5 : B
Day 6-7.5 : A
Total number of days A has worked = 2+1.5 = 3.5 days
Total number of days B has worked = 2+3 = 5 days
Work done by A : work done by B
3.5 *(1/6)*1008 : 5*(1/12)*1008
588 : 420