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JEE Mains · Maths · STD 11 - 6. permutation and combination

Let \(A\) be a \(3 \times 3\) matrix having entries from. the set \(\{-1,0,1\}\). The number of all such matrices A having sum of all the entries equal to \(5\) , is

  1. A \(478\)
  2. B \(414\)
  3. C \(456\)
  4. D \(421\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(414\)

Step-by-step Solution

Detailed explanation

Case-I: \(\quad 1 \rightarrow 7\) times and \(-1 \rightarrow 2\) times number of possible matrix \(=\frac{9 !}{7 ! 2 !}=36\) Case-II: \(\quad 1 \rightarrow 6\) times, \(-1 \rightarrow 1\) times and \(0 \rightarrow 2\) times number of possible matrix \(=\frac{9 !}{6 ! 2 !}=252\)…