The half-life of a radioactive kind of sodium is 15 hours. How much will be left after 45 hours, if you start with 80 grams of it? ​

its 4 because 2 times 2 is 4, if you double the number two you get four

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

inverse operation of addition