Grandma lucile bought some cloth. she used 7 freet to make a table cloth. she used 25 feet to make curtains. she used 6 feet to make a bag. she has 18 feet of cloth left. how much cloth did grandma lucile buy at first?

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b