A, B, C, D can complete a work in 3, 6, 9, 12 hours respectively. Further, only one person can work at a time in each hour and nobody can work for two consecutive hours. It is not necessary to engage all. What is the minimum number of hours that they will take to finish the work ?

Two persons A and B complete a task in 15 days, when they work together. Person A completes the task in 20 days if he works alone. How many days will B take to finish the task alone?

Eight men and 24 women can finish a piece of work in one day while 12 men and 18 women can also finish it in one day. What is the time taken by 24 men and 72 women to finish the work?

A can complete a particular task in 25 days whereas B can finish that task in 15 days. A and B together do the work for 5 days and then A leaves the task. How many days will B take to complete the re…

If 4 men or 6 women can do a piece of work in 12 days working 7 hours a day. How many days will it take to complete a work twice as large with 10 men and 3 women working together 8 hours a day?

A, B, and C can complete a work in x, 1.5x and 2x days respectively. If they complete the work together, in what ratio should they be paid?