Me/U2FsdGVkX1%252FG laazn%25295%252FGZince%252FSmok4B3W VDOKSXXO SHOCO In the question
After how many days will they have
the same amount of money?
The question is asking you to find the number of

Use pythagorean’s theorem and find the missing side lengths of the two smaller triangles and add them together
13^2 - 12^2 = 5
15^2 - 12^2 = 9
5+9 = 14
14 is the length of each side of the square
14^2 + 14^2 = 19.8
19.8 is the diagonal length of the inside if the square