JEE Main 2019 Mathematics question
In a class of 140 students numbered 1 to 140, all even numbered students opted Mathematics course, those whose number is divisible by 3 opted Physics course and those whose number is divisible by 5 opted Chemistry course. Then the number of students who did not opt for any of the three courses is:
Answer: (D)
Solution
|A∪B∪C| = 70 + 46 + 28 − 23 − 14 − 9 + 4 = 102 ⇒ 140 − 102 = 38.