41.
If 12 carpenters, working 6 hours a day, can make 460 chairs in 24 days, how many chairs will 18 carpenters make in 36 days, each working 8 hours a day ?

42.
If 5 spiders can catch five files in five minutes, how many files can hundred spiders catch in 100 minutes ?

43.
2 persons working 2 hours a day assemble 2 machine in 2 days. The number of machines assemble by 6 persons working 6 hours a day in 6 day is ?

44.
A wall of 100 meters can be built by 7 men or 10 women in 10 days. How many days will 14 men and 20 women take to build a wall of 600 metres ?

45.
21 binders can bind 1400 books in 15 days. How many binders will required to bind 800 books in 20 days ?

46.
If 17 labourers can dig a ditch 26 m long in 18 days, working 8 hours a day; how many more labourers should be engaged to dig a similar ditch 39 m long in 6 days, each labourer working 9 hours a day ?

47.
20 men complete one-third of a piece of work in 20 days. How many more men should be employed to finish the rest of the work in 25 more days ?

48.
A rope makes 70 rounds of the circumference of a cylinder whose radius of the base is 14 cm. How many times can it go round a cylinder with radius 20 cm ?

49.
A contract is to be complete in 46 days and 117 men were set to work, each working 8 hours a day. After 33 days, $$\frac{4}{7}{\text{ }}$$ of the work is completed. How many additional men may be employed so that the work may be completed in time, each man now working 9 hours a day ?

50.
12 persons can do a piece of work in 4 days. How many persons are required to complete 8 times the work in half the time ?