Quantitative Reasoning – Percentage and their equivalent fractions!

2014_QNR 2. A class of students was asked who had seen the movie The Life of Pi and who had seen the movie Finding Nemo. Twenty students had seen at least one of these movies.20% of the students had seen neither of these movies . How many students were in the class?

a) 40

b) 24

c) 25

d) 36

Ans:- In aptitude exams, percentage section forms a major portion of questions based on arithmetic; we should be comfortable with percentage and their equivalent fractions. By that, we encourage students to see 20% as 1/5 and 80% as 4/5 and vice-versa.

Clearly the number of students should be a multiple of 5. We should be able to choose option a) 40 and option c) 25.

A little calculation will tell you that 80% or 4/5 of the total students should be equal to the number of students who had seen any movie. 4/5th of 25 =20 . Option c) 25

[Or you can also think that had the total number of students be 40; 20 watched movies and other 20 did not- ratio of the two groups is 1:1 but it contradicts the fact that only 20% watched movies].

Students No Movie (20%) Movie (80%)
40 8 32
25 5 20

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