A and B can do a piece of work in 45 days and 40 days respectively. They began the work together, but A left after some days and B finished the remaining work in 23 days. After how many days did A leave? MCQ with Answer and Explanation
A and B can do a piece of work in 45 days and 40 days respectively. They began the work together, but A left after some days and B finished the remaining work in 23 days. After how many days did A leave?
A. 12 days
B. 6 days
C. 8 days
D. 9 days
Answer: Option D
Solution (By JKSSB Mock Tests)
Total work = LCM(45, 40) = 360 units. Efficiency of A = 8, B = 9. B worked alone for 23 days, so work done = 23 * 9 = 207 units. Remaining work = 360 - 207 = 153 units. This was completed by A and B together. Combined efficiency = 8 + 9 = 17. Time worked together = 153 / 17 = 9 days. Thus, A left after 9 days.
A and B can do a piece of work in 12 days, B and C in 15 days, and C and A in 20 days. If A, B and C work together, in how many days will they complete the work?
A group of men decided to do a work in 10 days, but 5 of them became absent. If the rest of the group did the work in 12 days, find the original number of men.
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