A can do a piece of work in 120 days and b can do it in 150 days . They work together for 20 days then b leaves and a continues the work alone .12 day after c join in place of b and the work is completed in 48 days more . In how many days can c do it if he work alone? Solution
Answers
C is correct answer I think
A can complete a work in 80 days and B can complete a work in 120 days. Take LCM for 80 and 120. So we have 240 total units.
A =24080=3=24080=3 units/day
B =240120=2=240120=2 units/day
One day's work of A+B is 55 units. So in 2020days, they will complete 100100 units.
Remaining (240−100)=140(240−100)=140 units. Then B worked for another 1212 days. So B complete (12×2)=24(12×2)=24 units. Remaining is (140−24)=116(140−24)=116 units.
After completing 124124 units C joined B and completed remaining 116116 units in 2828 days.
(B's one day work × 28)+(C's one day work×28)=116 units.
(C's one day work × 28) =116−(2×28)=116−56=60=116−(2×28)=116−56=60
C's one day work =6028=157=6028=157 units/day.
Hence C alone can complete the work in 240(157)=240×715=112240(157)=240×715=112 days.