1. If 8 men can do a piece of work in 20 days, in how many days could 20 men do the same work?

2. If an amount of food last for 40 days for 120 men, how long will it last for 80 men at the same rate?

3. If 18 women can reap a field in 7 days, in what time can 6 women reap the same field?

4. 10 men can dig a trench in 15 days. How long will 3 men take?

5. 3 lambs finish eating turnips in 8 days. In how many days will 2 lambs finish them?

6. 6 pipes are required to fill a tank in 1 hour. How long will it take if only 5 pipes of the same type are used?

7. 40 cows can graze a field in 16 days. How many cows will graze the same field in 10 days?

8. If x = ky and when y = 4, x = 8 then k =

9. x and y vary inversely with each other. If x - 15 when y = 6, then the value of x when y = 15 is

10. If 12 workers can build a wall in 50 hours, how many workers will be required to do the same work in 40 hours?