A piece of paper can be made into a cylinder in two ways: by joining the short sides together, or by joining the long sides together. Which cylinder would hold more? How much more?

It would hold more if you roll up the long sides. It would hold about 5x more than it would if it was rolled up by the short side

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

where are the choices?