Erin is sorting through the library books to decide which ones to replace. She finds 8 less than 6 times as many obsolete books as damaged books. If she removes 69 books total, how many books were damaged?
Erin is sorting through the library books to decide which ones to replace. She finds [NUMBER] less than [NUMBER] times as many obsolete books as damaged books. If she removes [NUMBER] books total, how many books were damaged?
Let o be the number of obsolete books and d be the number of damaged books. We know that o + d = 69 and o = 6d - 8.
Substituting the first equation into the second equation, we get 6d - 8 + d = 69
Combining like terms, we get 7d - 8 = 69
Adding 8 to both sides, we get 7d = 77
Dividing both sides by 7, we get d = 11
#### 11