Jay can buy a stereo either online or at a local store. if he buys online, he gets 15% discount, but has to pay a $12 shipping fee. at the local store, the stero is not on sale, but thereis no shipping fee. for what regular price is it cheaper for jay to buy the stereo online?

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