2002 AMC 8 Problem 19

Below is the professionally curated solution for Problem 19 of the 2002 AMC 8, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2002 AMC 8 solutions, or check the answer key.

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Concepts:digitscasework

Difficulty rating: 1390

19.

How many whole numbers between 9999 and 999999 contain exactly one 0?0?

7272

9090

144144

162162

180180

Solution:

Note that the 00 digit can either be the tens or the units digit. This gives us 22 options for this.

There are 99 options for each of the other digits for a total of 299=162 2 \cdot 9 \cdot 9 = 162 numbers.

Thus, D is the correct answer.

Problem 19 in Other Years

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