Four out of five days were used to create a problem, how many day will it take to solve it?

To determine how many days it will take to solve the problem, we need to consider the information given. We know that four out of five days were used to create the problem.

Let's break it down step by step:

1. Start with the total number of days needed to create the problem, which is five days.
2. Subtract the number of days used to create the problem, which is four days.

Using subtraction, we have:
5 - 4 = 1

Therefore, it will take one day to solve the problem.