An intern wants to label folders with numbers using digit stickers only. If the intern uses 999 stickers, how many folders have been numbered? (The numbers of the folders are consecutive and the number of the first folder is 1).	Choose the correct choice from the following choices:
A) 287
B) 369
C) 370
D) 371
E) 430

Rationale: for the first 9 folders we need 9 stickers . for the next 90 we need 2 stickers each or 180 stickers . for the next 900 folders we need 3 stickers each . the first 99 folders correspond to 189 stickers . subtract 189 from the total number of stickers ( 999 ) . this leaves 810 stickers for folders that use 3 stickers each . so , divide 810 by 3 to get 270 folders . add 99 folders to 270 folders to get the total number of folders , 369 . answer : b
Answer: B