there are 1000 students and 1000 lockers student 1 opened every locker in the school student 2 closed every even number locker student 3 opened or closed every 3rd locker student 4 opened or closed every 4th locker.

How many lockers are open what are the locker numbers?

Solution:

1000+1000/2+1000/3+1000/4 = 2083

So 2083 lockers are open