# Chain Rule: Learn Concept and Tricky Questions

In this video, we learn the concept of Chain Rule in detailed with two very important tricky questions.

[1] 40 carpenters working 8 hours a day can make 20 chairs in 60 days. After 30 days, an order of 10 more chairs came. To complete the total work on time, how many more hours per day they will have to work?

(a) 2

(b) 4

(c) 8

(d) None of these

[2] A garrison of 3300 men has provisions for 32 days when supplied at the rate of 850 grams per head. At the end of 7 days, a reinforcement arrives, and it is found that the provisions can last for 17 days more when supplied at the rate of 825 grams per head. What is the strength of the reinforcement?

(a) 1000

(b) 1700

(c) 2000

(d) 2500