In an examination, 19% of the students failed in English, 23% failed in Mathematics and 9% failed in both. What percentage of students passed in both subjects?

💡 Solution & Explanation

Students who failed in at least one subject = failed in English + failed in Mathematics − failed in both (they were counted twice) = 19 + 23 − 9 = 33%. So the students who passed in both = 100 − 33 = 67%. Forgetting to subtract the 9% who failed in both gives 58%, which is too low.