Question

In an examination, 35% candidates failed in one subject and 42% failed in another subject while 15% failed in both the subjects.if 551 candidates passed in both the subjects,how many candidates appeared in the examination?

Answer 1

Failed in one subject(A) = 35%
failed in another subject(B) = 42%
failed in both subjects(A Π B) = 15%

Total failed(A U B) = A + B - A Π B = 35 + 42 - 15 = 62%
Total Passed candidates = 100 - 62 = 38%
Total passed candidates = 551
So 38% of total candidates = 551
total candidates = 551×100 / 38 = 1450

1450 students had appeared in the examination.