279
To count the total digits used in numbering 129 pages, we split the page numbers into groups based on the number of digits.
Pages 1 to 9 (1-digit numbers): There are 9 pages, each using 1 digit.
Digits used = \(9 \times 1 = 9\)
Pages 10 to 99 (2-digit numbers): There are \(99 - 10 + 1 = 90\) pages, each using 2 digits.
Digits used = \(90 \times 2 = 180\)
Pages 100 to 129 (3-digit numbers): There are \(129 - 100 + 1 = 30\) pages, each using 3 digits.
Digits used = \(30 \times 3 = 90\)
Total digits = \(9 + 180 + 90 = 279\)
Hence, the correct answer is 279.
Important Questions from Number System
- The number 253118139 is divisible by which of the following?
- The number of prime numbers lying between 476 and 485, both included, is:
- The product of two consecutive natural numbers is 6. The greater of the two numbers is:
- Which of the following numbers divides 386937355?
If 1 is added to each odd digit and 2 is subtracted from each even digit in the number 8317456, what will be the sum of the digits that are second from the left and second from the right?
