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1. A palindrome is a word which is similar if read from backwards. Eg ‘ARORA’. Find the number of such 5 letter palindromes.

  • A. 676
  • B. 676
  • C. 676
  • D. 676

Answer: Option B

Explanation:

The first letter can be chosen in 26 ways. Similarly, second letter can be chosen in 26 ways.

Hence, the first 2 letters can be chosen in 26 × 26 ways.

Also, the third letter can be chosen in 26 ways.

Hence, the first 3 letters can be chosen in 26 × 26 × 26 ways.

But the fourth letter should be similar to second letter. This can be done in just 1 way.

Similarly, fifth letter should be similar to first letter. This can be done only in 1 way.

Hence, number of words possible = 26 × 26 × 26 × 1 × 1

= 17576


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