# Chain Rule - Important Formulas, Questions and Study Material

**Chain Rule Important Questions - Page 3**

** Chain Rule Video Lecture - Page 4**

When quantities of different kinds are connected to one another so that we know how much of one quantity is equivalent to a given quantity of a second, etc. We can determine how much of the last kind is equivalent to a given of first kind by the chain rule.

## Proportion and Indirect Proportion

If increase or decrease of a quantity causes increase or decrease of another quantity in the same extent then, is directly proportional to

* 1)* Number of persons Amount of work done, i.e. more persons, more work

* 2)* Number of days Amount of work, i.e. more days, more work

* 3) *Working rate Amount of work, i.e. more working rate, more work

* 4) *Efficiency of man Amount of work, i.e. more efficiency of man, more work

Combining I,II,III,and IV, Amount of work. If increase of a quantity

**5)** Number of men , i.e. more the men, less the no. of days required

## Chain Rule Important Formulas

1)

Remember, “Man days” required per unit work is always same. In fact, specify the volume of job or work.

2) If in place of men there are engines burning coal for certain number of hours, then, the above equation changes to

Because, here the job of engine is to burn the coal.

3) If number of examiners examining a number of answer books in number of days by working a number of hours or day, since the job of examiner is to check the answer books,

then,