Problems on Chain rule with answers

Introduction

Are you struggling for clearing the first round during the interview or competitive exams? Mainly aptitude sums will be asked in the first round of the interview process. Work out chain rule aptitude questions and answers to overcome those struggles. Formulas on chain rule with answers are given on the Nithra Jobs site.

Formulas to use:

1. Direct Proportion

Two quantities are said to be directly proportional, if on the increase (or decrease) of the one, the other increases (or decreases) to the same extent.

Ex:

Cost is directly proportional to the number of articles.

(More articles, More cost)

2. Indirect Proportion (inverse proportion)

Two quantities are said to be indirectly proportional, if on the increase of the one, the other decreases to the same extent and vice-versa.

Ex:

The time taken by a car is covering a certain distance is indirectly proportionalto the speed of the car. (More Speed, Less is the time taken to cover a distance.)

Note: In solving problems by chain rule, we compare every item with the term to be found out.

Solved Problems:

1. In a dairy farm, 30 cows eat 30 bags of husk in 30 days. In how many days one cow will eat one bag of husk?

Answer: 30 days

Explanation:

Assume that in x days, one cow will eat one bag of husk. More cows, less days (Indirect proportion)

More bags, more days (direct proportion) Hence we can write as

Cow => 30 : 1 :: x : 30

Bags => 1 : 30 :: x :: 30

30 * 1 * 30 = 1 * 30 * x

( 30 * 30 ) = 30 x

x = ( 30 * 30 ) / 30

= 30 days

The required days = 30 days

2. 36 men can complete a piece of work in 9 days. In how many days will 27 men complete the same work?

Answer: 12 days

Explanation:

Let the required number of days be x More men, less days (indirect proportion) Hence we can write as

36 : 27 :: x : 9

36 * 9 = 27 * x

( 36 * 9 ) / 27 = x

36 / 3 = x

x = 12

The required days = 12 days

3. 39 persons can repair a road in 6 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work?

Answer: 6.5 days

Explanation:

Let the required number of days be x

More persons, less days (indirect proportion) More hours, less days (indirect proportion) Hence we can write as

Persons => 39 : 30 :: x : 6

Hours => 5 : 6 :: x : 6

39 * 5 * 6 = 30 * 6 * x

39 * 30 = 180 x

( 39 * 30 ) / 180 = x

( 39 * 3 ) / 18 = x

39 / 6 = x

x = 6.5 days

The required days = 6.5 days

4. If the wages of 6 men for 15days be Rs. 2100, then find the wages of 12 men for 9 days.

Answer: Rs.2520

Explanation:

Let the required wages be Rs. x

More men, More wages (direct proportion) Less days, Less wages (direct proportion) Men => 6 : 12 :: 2100 : x

Days => 15 : 9 :: 2100 : x

( 6 * 15 * x ) = ( 12 * 9 * 2100 )

90 x = ( 12 * 9 * 2100 )

x = ( 12 * 9 * 2100 ) / 90

= ( 12 * 2100 )/ 10

= 12 * 210

= 2520

The required wages = Rs. 2520

5. A certain number of men can complete a piece of work in 180 days. If there are 30 men less, it will take 20 days more for the work to be completed. How many men were there originally?

Answer: 300

Explanation:

They were to complete the work in 180 days but as the number of persons is reduced to x - 30.

Work takes 20 more days. So the equation is 180x = (x - 30) 200 180x = 200x - 6000

200x - 180x = 6000

20x = 6000

x = 6000 / 20

x = 300

Total number of mens = 300

Conclusion

Daily practising of chain rule questions and answers will train you to sove the problems with in a minute. So practise daily by visiting Nithra Jobs app.