A and B together can complete a piece of work in 30 days. They worked together for 20 days and then B left. After another 20 days, A finished the remaining work. In how many days can A alone complete the work?

If 18 men working 7 hours a day can prepare 14 school uniforms in 20 days, then in how many days can 12 men working 6 hours a day prepare 18 school uniforms?

Raju alone can complete a work in 36 days, and Raj alone can complete the same work in half the time taken by Raju. How many days will they take together to complete 14 of the total work?