CAT Quantitative Aptitude Questions | CAT Set theory Questions - Union and Intersection

CAT Questions | Set theory | Union and Intersection

The question is from CAT Set theory. It is about venn diagrams. We just need to draw the diagram without any mistakes to solve this one. CAT exam is known to test on basics rather than high funda ideas. CAT also tests multiple ideas in the same question, and 2IIMs CAT question bank provides you with CAT questions that can help you gear for CAT Exam CAT 2023. Set Theory (especially constructing venn diagrams) is a frequently tested topic. Make sure you know the basics from this chapter.

Question 20: In a survey it was found that 10% people don’t use Facebook, Twitter or Whatsapp.8% uses all the three. There are 15% who use Facebook and Twitter only, 20% who use Twitter and Whatsapp only and 20% who use Facebook and Whatsapp only. Number of people that use only Facebook, only Twitter and only Whatsapp are equal. If the survey was conducted on 1000 people, answer the following:

  1. How many people use Whatsapp only?
    1. 20
    2. 9
    3. 15
    4. 90
  2. What is the ratio of number of people that uses Whatsapp only to the people using either Whats app or Facebook or both?
    1. \\frac{1}{6}\\)
    2. \\frac{25}{75}\\)
    3. \\frac{1}{3}\\)
    4. \\frac{1}{9}\\)

Best CAT Online Coaching
Try upto 40 hours for free
Learn from the best!


2IIM : Best Online CAT Coaching.


Best CAT Coaching in Chennai


CAT Coaching in Chennai - CAT 2022
Limited Seats Available - Register Now!


Explanatory Answer

Method of solving this CAT Question from Set theory: If you get the Venn Diagram right, you are halfway through !!

Let the no. of people that use only Facebook = only Twitter = only Whatsapp = x
Let’s construct of venn diagram:
CAT Question - Set theory2
From the figure we can see that x + x + x + 8 + 20 + 20 + 15 + 10 = 100
=> 3x = 100 – 73
=> x = \\frac{27}{3}\\) = 9
1. Thus the of no people who use Whatsapp only = 9% or 9 x 1000/100 = 90
2. % of people that use Whatsapp only = 9
% of people that use either Whatsapp or Facebook or both = 20 + 20 + 8 + 9 + 9 +15 = 81
Thus the ratio = \\frac{9}{81}\\) = \\frac{1}{9}\\)

The question is "How many people use Whatsapp only?"

The question is "What is the ratio of number of people that uses Whatsapp only to the people using either Whats app or Facebook or both?"

Hence, the answer is "90 and \\frac{1}{9}\\)" respectively.


CAT Online Coaching | CAT Arithmetic Videos On YouTube


Other useful sources for Arithmetic Questions | Set Theory Sample Questions


CAT Questions | CAT Quantitative Aptitude

CAT Questions | CAT DILR

CAT Questions | Verbal Ability for CAT


Where is 2IIM located?

2IIM Online CAT Coaching
A Fermat Education Initiative,
58/16, Indira Gandhi Street,
Kaveri Rangan Nagar, Saligramam, Chennai 600 093

How to reach 2IIM?

Phone: (91) 44 4505 8484
Mobile: (91) 99626 48484
WhatsApp: WhatsApp Now
Email: prep@2iim.com