August 2020
Problem of the Month

How Many Pages?

To number the pages in a math book, the printer used 2,989 digits.

How many pages are in the book?

Solution to the Problem:

The answer is 1,024 pages.

A book of 99 pages needs 9 + 2 x 90 = 189 digits.
A book of 999 pages needs 9 + 2 x 90 + 3 x 900= 2,889 digits.
A book of n pages needs 2,889 + 4 x (n - 999) digits.
Set 2889 + 4 (n - 999) = 2,989.
Then n = 1024 pages

Correctly solved by:

1. Ivy Joseph	Pune, Maharashtra, India
2. Colin (Yowie) Bowey	Beechworth, Victoria, Australia
3. Joshua Mangin	---------
4. Katherine Grossman	Redlands Middle School, Grand Junction, Colorado
5. Kamri Hutchings	Mountain View High School, Mountain View, Wyoming
6. Adan Vargas	Mountain View High School, Mountain View, Wyoming

Send any comments or questions to: David Pleacher