In an examination 35% of candidates failed in one subject and 42% failed in another subject while 15% failed in both the subjects. If 2500 candidates appeared at the examination how many passed in either subject but not in both?

In an examination 35% of candidates failed in one subject and 42% failed in another subject while 15% failed in both the subjects. If 2500 candidates appeared at the examination how many passed in either subject but not in both? Correct Answer 1175

Given:

35% of candidates failed in one subject.

42% failed in another subject.

15% failed in both the subjects.

Total candidates = 2500

Concept:

Here we will be using te concept of venn diagram. However we don't need to draw the diagram for basic problems involving only 2 variables.

Solution:

Number of students appear in the exam = 2500

Number of students failed in 1^st subject = 2500 × (35/100) = 875

Number of students failed in 2^nd subject = 2500 × (42/100) = 1050

Number of students failed in both = 2500 × (15/100) = 375

Now, number of students failed in 1^st subject only = 875 – 375 = 500

And, number of students failed in 2^nd subject only = 1050 – 375 = 675

∵ Students who are failed in only 1 subject, are passed in other subject

∴ Required answer = Number of students failed in only 1 subject

= 675 + 500 = 1175