When a non-negative integer is divided by 5, we get a remainder such that the number can be represented as . For an explicit example if , then we have . And note that the remainder, here, is 1.
If I give you three chances to enter the integer , what is the probability that you will get the question right on the third attempt?
Clarification:
You will have to come up with a valid option (a possible remainder which we get after division by 5) each time you enter an integer.
The remainder is defined being bounded in the interval