Subject
Quantitative Aptitude
Topic
Permutation & Combination
A palindrome is a word which is similar if read from backwards. Eg ‘ARORA’. Find the number of such 5 letter palindromes.
A palindrome is a word which is similar if read from backwards. Eg ‘ARORA’. Find the number of such 5 letter palindromes.
ক)
676খ)
17576গ)
456976ঘ)
30522Explanation
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 = 17576Related questions
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