In lock and key factory, one machine produces only locks at the rate of 100 locks per minute and needs to be cleaned for 5 minutes after production of every 1000 locks Another machine produces only keys at the rate 75 keys per minute and needs to be cleaned for 10 minutes after production of every 1500 keys, If both the machines start production at the same time, what is the minimum duration in minutes required for producing 9000 pairs of locks and keys?

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…

In the bottom of a water tank, there are two drains A and B. If only A is open, it takes 30 minutes to empty a full tank and if only B is open, it takes 20 minutes. If for 10 minutes both drains are…

50 men can complete a work in 40 days. They begin the work together but a batch of 5 men left after each period of 10 days. What is the time to complete the work?

Mohan can do a bit of work in 25 days which can be completed by Sohan in 20 days. Both together labour for 5 days and afterward Mohan leaves off. How long will Sohan take to complete the remaining wo…

X and Y Can do a piece of work in 45 days and 40 days respectively. They begin to work together, but X leaves after n days and then Y completes the remaining work in 23 days. What is n equal to ?