Your teacher on Monday says she will give you a test this week, but you will not know what day it will be when you are given it. What day will she give the test?

No. It cannot be on Sunday, because you would know ahead of time. Thus it cannot be on Saturday similarly. Thus, it is a paradox. You've got to exercise your minds if you want to tutor.

It does not matter how many days you have. It cannot be the last day, because then the kids would already know what day it was (because it hasn't come yet). But then we eliminate that day, and it cannot be the last of the remaining days...