A and B together can plough a field in 10 hours but by himself A requires 15 hours. How long would B take to plough the same field?

A and B can separately complete a piece of work in 20 days and 30 days respectively. They worked together for some time then B left the work. If A completed the rest of the work in 10 days, then B worked for how many days?

120 men consume 720 kg of rice in 30 days. In how many days can 90 men consume 270 kg?

A goldsmith observes that one of his employees prepares a necklace in 9 hours, while another employee prepares it in 10 hours. If they work together, they stud 10 gems less every hour and thus prepare a necklace in 5 hours, then the number of gems studded in each necklace is: 

Either 8 men or 17 women can paint a house in 33 days. The number of days required to paint three such houses by 12 men and 24 women working at the same rate is: 

Anil, Deepak, and Dinesh together can complete a work in 35 days. Anil and Dinesh together can complete the same work in 60 days. In how many days Deepak alone can complete the same work?

A and B can do a piece of work in 20 days and 30 days respectively. They started the work together but after 8 days they doing work in alternate days, started with B. how many days the work will be completed? 

Vinit and Gopal can do a work together in 4 days. Shyam and Mohan can do the same work in 12 days. So, in how many days can all four complete that work together?