If number of rows in matrix A is 10 and number of elements = 70 . Also if B has same rows as columns in matrix A . Then find number of columns in B if it has 21 elements  

Answers (1)

As we have learned

Compact form of matrix -

\large A= \left [ a_{ij} \right ],  \large 1\leq i\leq m

1\leq j\leq n

- wherein

aij - element of the ith row and jth column

m - no. of rows

n - no. of columns 

 

 Given m_A = 10 ; m_A \times n_A= 70

Thus n_A= 7

Also , m_B= n_A= 7 \; \; and\; \; n_B\times m_B= 21

Thus  n_B=3

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