In a stand there are 15 books. 5 of them are Mathematicsbooks.

What the probability of at least two are together?

Answer: At least 4/14 = 28.5%

Step-by-step explanation:

Select the location of a math book at the far end. The probability that the book next to it is a math book:

4 remaining math books, out of the 14 remaining books

In the middle, there are two potential spots adjacent to each book, so it could be higher - that's why I say "at least" 4/14