A palindrome is a number that reads the same from the left as well as from the right for example 237...........

Quantitative Aptitude Number System

A palindrome is a number that reads the same from the left as well as from the right, for example, 23732. What is the number of palindromes between 10 and 1010?

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EPFO APFC (2015)

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Explanation:

We can easily solve this problem using permutations.
First take the two-digit palindromes.
They would be 11,22,33,..... and 99. They are 9 in number.
Now consider 3-digit palindromes from 100 to 200.
They are 101, 111, 121,.....191. These are 10 in number.
In the same way, from 200-299: 10 palindromes
300-399: 10
400-499: 10
500-599: 10
600-699: 10
700-799: 10
800-899: 10
900-999: 10
The last palindrome would be 1001.
So we got 100 palindromes in total between 10 and 1010.