Question

if 806 students failed in an examination and 75% passed find the total number of students​

Answer 1

Answer:

Let A be the set of students passed in English and B be the set of students who passed in maths.

Since 25% failed in both, percentage of students who passed at least one subject is (100–25)% = 75%. ie n(AUB) =75 if we take 100 as the total number of students.

But n(AUB) = n(A)+n(B) - n(AnB)

=> n(AnB) = 75+60–75 = 60

So percentage of students who passed the exam is 60%

So 60% of the students = 240

100% of the students = 240/60 × 100 = 400

So total number of candidates= 400

Step-by-step explanation:

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