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AP EAMCET · Maths · Permutation Combination

A string of letters is to be formed by using 4 letters from all the letters of the word "MATHEMATICS". The number of ways this can be done such that two letters are of same kind and the other two are of different kind is

  1. A \(756\)
  2. B \(252\)
  3. C \(840\)
  4. D \(360\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(756\)

Step-by-step Solution

Detailed explanation

Letters with duplicates: M, A, T (3 types). Total distinct letters: 8. Choose 1 letter type for the pair: \(\binom{3}{1}\) Choose 2 distinct letter types from the remaining 7 distinct types: \(\binom{7}{2}\) Number of letter combinations:…