### CAT / #Quantitative Ability

October 28, 2017 @ 11:42 AM

October 28, 2017 @ 11:42 AM

# Quantitative Ability - Chain Rule

Important Formulas:

### 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.

E.g. Cost is directly proportional to the number of articles. (More Articles, More Cost)

### 2. Indirect Proportion:

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

E.g. The time taken by car is covering a certain distance is inversely proportional to the speed of the car. (More speed, Less is the time to cover a distance.)

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

Solved Illustrations:

### Question 1)

If the cost of X meters of wire is d rupees, then what is the cost of y meters of wire at the same rate?

A) Rs. xy/d

B) Rs. yd/x

C) Rs. (yd)

D) Rs. (xd)

Solution:

Cost of x metres = Rs. d.

Cost of 1 metre = Rs. d/x

Cost of Y metres = Rs. (d/x * x.y) = rs. yd/x

### Question 2)

39 persons can repair a road in 12 days, working 5 hours a day. In how many days will 30 persons, working 6 hours a day, complete the work

A) 10

B) 13

C) 14

D) 15

Solution

Let the required number of days be X.

Less person, more days (indirect proportion)

More working hours per day, Less days (indirect proportion)

Persons 30: 39
Working hours/days 6:5

Therefore, 30*6*x = 39*5*12

X = (39*5*12)

X= 13.

### Question 3)

If a quarter kg of potato costs 60 paise, how many paise will 200gm cost?

A) 48 paise

B) 54 paise

C) 56 paise

D) 72 paise

Solution: Let the required weight be x kg

Less weight, less cost (direct Proportion)

Therefore, 250:200::60:x = 250 x x = (200*60)

X = (200*60)/250

X = 48

### Question 4)

In a dairy farm, 40 cows eat 40 bags of husk in 40 days. In how many days one cow will eat on a bag of husk?

A) 1

B) 1/10

C) 40

D) 80

Solution:

Let the required number of days be x.

Less cows, more days (Indirect Proportion)

Less bags, Less days (Direct Proportion)

Cow 1:40
Bags 40:1

1*40*x =40*1*40

= x=40.

### Question 5)

A flagstaff 17.5 m high casts a shadow of length 40.25 m. The height of the building, which casts a shadow of length 28.75 m under similar conditions, will be:

A) 10.0 m

B) 12.5 m

C) 17.5 m

D) 21.25 m

Solution:

Let the height of the building x metres.

Less lengthy shadow, Less in the height (Direct Proportion)

40.25: 28.75: 17.5: X

40.25 * X = 28.75 * 17.5

X = 28.75*17.5/ 40.25

X = 12.5

Attempt CAT Mock Test Now

Read Complete Module on Quantitative Ability

Stay informed, Stay ahead and stay inspired with MBA Rendezvous

Crucial Dates, You Should not Miss

 Manav Rachna International Institute of Research Admissions Open for all MBA programme at Manav Rachna International Institute of Research and Studies. CII School of Logistics Amity University, Delhi and Mumbai Admissions Open at CII School of Logistics Delhi and Mumbai campus, Apply Now! GITAM School of International Business, Visakhapatnam Admissions open for MBA programmes at GITAM. Application Deadline is April 15, 2018 KIIT School of Management Admissions Open for MBA at KIIT School of Management through CAT/ MAT/ GMAT/ ATMA/ CMAT/ XAT Institute of Public Enterprise, Hyderabad Last Date to Apply for IPE, Hyderabad is 16 March, 2018 MDI Murshidabad Applications for PGPM 2018-20 at MDI Murshidabad are open TAPMI, Manipal Admission Open. Apply Now. Birla Global University Admission 2018 Open for MBA at Birla Global University