In an examination, 37% of the students failed in English, 40% failed in Mathematics and 20% 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) = 37 + 40 − 20 = 57%. So the students who passed in both = 100 − 57 = 43%. Forgetting to subtract the 20% who failed in both gives 23%, which is too low.