Time and Work Questions

An hour-long test has 60 problems. If a student completes 30 problems in 25 minutes, then the required seconds he has taken on average for computing each of the remaining problems is

Ramesh and Rahman can do a work in 20 and 25 days respectively. After doing collectively 10 days of work, they leave the work due to illness and Suresh completes rest of the work in 3 days. How many days Suresh alone can take to complete the whole work ?

A can do a piece of work in 10 days, B can do it in 12 days and C can do it in 15 days. In how many days will A, B and C finish it, working all together?

P does half as much work as Q in 1/3 of the time. If together they take 15 days to complete a work, how many days will P take to do it alone?

Atul can do a piece of work in 18 days, Aaravya is 50% more efficient than Atul. How much more time does Atul take than Aaravya to do the same piece of work?

P, Q and R alone can complete a work in 12, 15 and 20 days respectively. In how many days will they together complete the same work?

If 15 persons can do a job in 30 days, then 30 persons with twice the efficiency can do the same job in how many days?

12 men and 16 women together can complete a work in 4 days. It takes 80 days for one man alone to complete the same work, then how many days would be required for one woman alone to complete the same work?