Chain Rule - Questions and Answers

16. If 5 engines consume 6 metric tones of coal when each is running 9 hours day, how much coal will be needed for 8 engines, each running 10 hours a day, it being given that 3 engines of the former type consume as much as 4 engines of latter type ?

17. If 20 men can build a wall 112 metres long in 6 days, what length of a similar wall can be built by 25 men in 3 days ?

18. If 20 men working 7 hours a day can do a piece of work in 10 days, in how many days will 15 men working for 8 hours a day do the same piece of work ?

19. If 40 person consume 60 kg. of rice in 15 days, then in how many days will 30 persons consumer 12 kg. of rice :

20. If 3 person weave 168 shawls in 14 days, how many shawls will 8 persons weave in 5 days ?