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NDA 2020
Exam
NDA
Year
2020
Subject
Mathematics
Chapter
Matrices

NDA 2020 · Mathematics · Matrices

If A is a matrix of order 3 × 5 and B is a matrix of order 5 × 3 ,...

If AA is a matrix of order 3×53 \times 5 and BB is a matrix of order 5×35 \times 3, then the order of ABA B and BAB A will respectively be

Options

  1. A3×33 \times 3 and 3×33 \times 3
  2. B3×53 \times 5 and 5×35 \times 3
  3. C3×33 \times 3 and 5×55 \times 5
  4. D5×35 \times 3 and 3×53 \times 5

Correct answer

C. 3×33 \times 3 and 5×55 \times 5

Step-by-step solution

A=[i×j]3×5,B=[i×j]5×3A=[i \times j]_{3 \times 5}, B=[i \times j]_{5 \times 3} Now, AB=[i×j]3×3A B=[i \times j]_{3 \times 3} and BA=[j×i]5×5B A=[j \times i]_{5 \times 5}
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