In an examination 60% of students passed in Physics and 75% students passed in Chemistry. If 55% of students passed in both these subjects, then what per cent of students failed in both the subjects?

Question

Question

Answer 1

Given:

Students passed in Physics = 60%

Students passed in Chemistry = 75%

Students passed in both the subjects = 55%

Formula Used:

n(A U B) = n(A) + n(B) - n(A ∩ B)

n(A) + n(A)' = n(U)

Calculation:

n(A U B) = n(A) + n(B) - n(A ∩ B)

⇒ n(A U B) = 60% + 75% - 55%

⇒ n(A U B) = 80%

Total students = 100%

n(A) + n(A)' = n(U)

⇒ 100% - 80% = n(A)'

⇒ 20% = n(A)'

∴ 20% students failed in both the subjects

The correct answer is 20%

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