Working for 10 hours per day, 6 men can build a wall in a certain number of days. By working for how many hours/minutes per day can 12 men build the wall in the same days?

P, Q and R can finish a work in 5 days, 10 days, and 15 days, respectively, working alone. P and Q works on first day, P and R works on second day and P and Q works on third day and son on till the work is completed. In how many days the work will be completed?

A and B can complete a work together in 48 days. A is 4 times as work efficient as B. In how many days can B alone complete the work?

A and B together can complete a certain work in 20 days whereas B and C together can complete it in 24 days. If A is twice as good a work man as C, then in what time will B alone do 40% of the same work? 

Aarif, Arun and Abraham can do a work in 12, 20 and 24 days, respectively. They all begin together. Aarif leaves the work 1 day, Arun 3 days and Abraham 4 days before its completion. In how many days is the work finished?

A is 40% more efficient than B. How much time will both, working together, take to finish the work, which B alone can finish in 36 days?

Raju, Shobha and Mohan can do a work in 15 days, 20 days and 25 days respectively. In how many days, will the work be finished, if they do it on alternate days?

If Anju is 30% more efficient than Bitt, then how much time will they take, working together, to complete a job which Anju alone could have done in 23 days?