4 men, each working 6 hours per day can build a wall in 9 days. How long will 6 men, each working 3 hours per day take to finish the same work?

2 men each working 5 hour per day can finish a job in 12 days. How long will 4 men each working 2 hours per day take to finish the same job?

10 men working 8 hours day can do a work in 30 days. In how many days will 12 men working 4 hours a day take do the same work?

If 3 men or 6 boys can finish a work in 20 days, how long will 4 men and 12 boys take to finish the same work ?

3 men or 5 women can do a work in 12 days. How long will 6 men and 5 women take to finish the work?

24 men working at 8 hours per day can do a piece of work in 15 days. In how many days can 20 men working at 9 hours per day can complete the same work?