CSATNumber System & SeriesDigits Arithmetic2019

A printer numbers the pages of a book starting with 1 and uses 3089 digits in all. How many pages does the book have?

A

1040

B

1048

C

1049

D

1050

Correct Answer: Option C

Explanation

To solve this efficiently, we use the 'Range Segmentation' strategy learned from the 2017 PYQ analysis [1, 45]. \n\n1. **Establish Benchmarks from PYQ logic:**\n - Pages 1-9 (1 digit each): 9 pages × 1 = 9 digits [46].\n - Pages 10-99 (2 digits each): 90 pages × 2 = 180 digits [50].\n - Pages 100-999 (3 digits each): 900 pages × 3 = 2700 digits (As per the standard counts mentioned in [1, 23]).\n\n2. **Calculate Cumulative Total:**\n - Total digits for first 999 pages = 9 + 180 + 2700 = 2889 digits.\n\n3. **Compare and Find Excess:**\n - The question gives 3089 digits.\n - Excess digits = 3089 - 2889 = 200 digits.\n - Since we have crossed page 999, all subsequent pages are 4-digit numbers.\n\n4. **Calculate Remaining Pages:**\n - Pages in 4-digit range = Excess Digits / 4\n - Pages = 200 / 4 = 50 pages.\n\n5. **Final Addition:**\n - Total Pages = 999 (from previous ranges) + 50 (new 4-digit pages) = 1049 pages.\n\nThis matches Option C.

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