In a class, 22 students like drawing, 16 like music, and 6 like both. How many students like at least one activity?
Answer and explanation
Correct answer: 32
Let D be the set of students who like drawing and M the set who like music. Students liking at least one activity are in D ∪ M. By the inclusion-exclusion formula, n(D ∪ M) = n(D) + n(M) − n(D ∩ M) = 22 + 16 − 6 = 32. We subtract the 6 students who like both because they were counted twice.
Frequently asked questions
What is the correct answer to this question?
32
Why is this the correct answer?
Let D be the set of students who like drawing and M the set who like music. Students liking at least one activity are in D ∪ M. By the inclusion-exclusion formula, n(D ∪ M) = n(D) + n(M) − n(D ∩ M) = 22 + 16 − 6 = 32. We subtract the 6 students who like both because they were counted twice.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).