Percentage of students failed in English = n(E) = 50. Percentage of students failed in Hindi = n(H) = 40. Percentage of students failed in both English and Hindi = n(E∩H) = 15. We know, n(E∪H) = n(E) + n(H) – (E∩H)Percentage of candidates failed in at least one subject =50+40–15=75%. Percentage of candidates passed in both the subjects = 100%–75%=25%.