banksy
There are less than 50 books are to be divided by students. If the books are divided by 7 students, one book will be left. Haw many books are there?
(1) If the books are divided by 9 students, 8 books will be left.
(2) If the books are divided by 5 students, 3 books will be left.
Guess the book are to be divided
equally among the students.
You can solve this question algebraically with formulas though simple listing the possible values of the books would probably be easier and quicker.
If the books are divided by 7 students, one book will be left --> there could be 1, 8, 15, 22, 29, 36, or 43 book.
(1) If the books are divided by 9 students, 8 books will be left --> there are
8, 17, 26, 35, or 44 --> to satisfy the condition in the stem # of books could be 8 only. Sufficient.
(2) If the books are divided by 5 students, 3 books will be left --> 3,
8, 13, 18, 23, 28, 33, 38,
43, or 48 --> to satisfy the condition in the stem # of books could be 8 or 43. Not sufficient.
Answer: A.