A sample of 100 people was surveyed for the use of computers, cell phones and credit cards. 31 people had credit cards, 61 had computers and 28 had cell phones. If 11 people had none of the three and 32 people had more than one, how many had all the three?

A) 1

B) 2

C) 3

D) 4

E) 5

Solution: This is a question based on Set Theory.

Total = 100

None = 11

Net Total = 100 - 11

P(A) = Credit Cards = 31

P(B) = Computers = 61

P(C) = Cell Phones = 28

Using the formula, P(S) = P(A) + P(B) + P(C) - P(A?B) – P(B?C) – P(C?A) + P(A?B?C)

P (A?B) + P(B?C) + P(C?A) = 32 (More than One)

Plugging in values, we get,

100 – 11 = 31 + 61 + 28 – (P (A?B) + P(B?C) + P(C?A)) + P(A?B?C)

89 = 120 – (32 + P(A?B?C))

P(A?B?C) = 1**Correct Answer:** A

About the Author

GyanOne is an educational services firm focused on premium GMAT coaching, application advisory (with a focus on ISB applications), and interview preparation for B-school admissions. GyanOne operates in the New Delhi region of India and has top global B-school alumni with a minimum score of 770 on the GMAT, as instructors. All GyanOne counsellors are professionally trained top B-school alumni with an experience of 100+ MBA applications behind them.

Essential GMAT Reading Comprehension Guide

After reading F1GMAT’s Essential GMAT Reading Comprehension Guide, you will:

1. Complete GMAT RC Questions in less than 1 minute and 50 seconds

2. Read Faster

3. Take Notes Effectively

4. Collect and Interpret Facts

5. Speed up Summary Creation

6. Remember Information

7. Question the Author

8. Learn to Answer GMAT Reading Comprehension Title question

9. Learn to Answer GMAT Reading Comprehension Main Idea Question

**(2019 Edition) (100+ New Questions)**

Mastering GMAT Critical Reasoning

After you read F1GMAT’s Mastering GMAT Critical Reasoning Guide, you will learn:

How to overcome flawed thinking in GMAT Critical Reasoning?

**(2019 Edition) (25+ New Questions)**