One hundred lockers are numbered in order. Every fourth locker is marked red, and every sixth locker is marked blue. How many lockers have at least one mark?
Show hints
- Count every fourth and every sixth locker separately.
- Count lockers with two marks only once.
Show the answer and solution
Answer: 33
A red mark appears on 25 lockers and a blue mark on 16. Eight lockers whose numbers are divisible by 12 were counted twice. Therefore, 25 + 16 − 8 = 33.