In a group of 60 students, 35 can swim, 30 can ride a bicycle and 12 can do both. How many students can do neither?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 7
The students who can do both are counted once among the swimmers and once among the cyclists, so they are subtracted once: \(n(A\text{ or }B)=n(A)+n(B)-n(\text{both})\).
Swim only \(=35-12=23\)
Cycle only \(=30-12=18\)
Swim or cycle (or both) \(=35+30-12=53\)
Neither \(=60-53=7\)
