There are at least three grammatical errors in the stem itself, so this might be a good SC question. I assume the question is saying we have between 50 and 60 books. Statement 1 says when we divide that number by 3, the remainder is 1. So we could have 52, 55 or 58 books (any number between 50 and 60 that is one larger than some multiple of 3). Statement 2 says when we divide that number by 6, the remainder is 1, so we must have 55 books, and the answer is B.