In a group, 20 students like Mathematics, 15 like Science, and 8 like both. How many like only Mathematics?
Answer and explanation
Correct answer: 12
Let M represent students who like Mathematics and S represent students who like Science. The 20 students in M include the 8 students who like both subjects. To count only Mathematics, remove the overlap: n(M − S) = n(M) − n(M ∩ S) = 20 − 8 = 12. Thus, 12 students like Mathematics but do not like Science.
Frequently asked questions
What is the correct answer to this question?
12
Why is this the correct answer?
Let M represent students who like Mathematics and S represent students who like Science. The 20 students in M include the 8 students who like both subjects. To count only Mathematics, remove the overlap: n(M − S) = n(M) − n(M ∩ S) = 20 − 8 = 12. Thus, 12 students like Mathematics but do not like Science.
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Sets. Topic: Operations on Sets (Union, Intersection, Difference).