CAT Questions | CAT LR DI

CAT DI LR section has become increasingly tough beginning from 2015. However, Understanding the basics of Bar graphs, Pie Charts, Multiple graphs, Line Graphs etc forms an integral part of solving tougher CAT level DI LR questions for the CAT Exam. This question is from CAT 2017 Slot 1 CAT DILR.

CAT DILR : 2017 slot 1 questions

Cars Travel Route

A new airlines company is planning to start operations in a country. The company has identified ten different cities which they plan to connect through their network to start with. The flight duration between any pair of cities will be less than one hour. To start operations, the company has to decide on a daily schedule.

The underlying principle that they are working on is the following:

Any person staying in any of these 10 cities should be able to make a trip to any other city in the morning and should be able to return by the evening of the same day.

Question 3: Suppose the 10 cities are divided into 4 distinct groups G1, G2, G3, G4 having 3, 3, 2 and 2 cities respectively and that G1 consists of cities named A, B and C. Further, suppose that direct flights are allowed only between two cities satisfying one of the following:

1. Both cities are in G1
2. Between A and any city in G2
3. Between B and any city in G3
4. Between C and any city in G4

Then the minimum number of direct flights that satisfies the underlying principle of the airline is: (TITA)

Video Explanation

Explanatory Answer

Method of solving this Question on CAT DILR

General Solution



First consider the flights to G2.
But, only flight from and to A can be allowed for cities in G2.


So, between A and G21, 4 flights should be operated (morning/evening and to/from).
Similarly between A-G22 and A-G23.
Total flight = 4 + 4 + 4 = 12 flights
Similarly, G3 consists of two cities and can only be connected to city B.
Therefore, total flights = 4 + 4 = 8.
And, for G4 flights are connected only to city C.
Total flights = 4 + 4 = 8
Finally, we have to consider flights within G1.
As stated in the previous questions, the total number of flights between the hub cities is 4 + 4 + 4 = 12.
Minimum no. of flights to be opeated = 12 + 8 + 8 + 12 = 40 flights.

The question is "The minimum number of direct flights that satisfies the underlying principle of the airline is: "

Hence, the answer is "40".