When courtney collected her change she realized she had five times as many dimes as quarters. her dimes and quarters totaled $5.25. how many quarters did she have?

Dimes (0.10): 5Q

Quarters (0.25): Q

 Dimes  + Quarters = Total

0.10(5Q) +  0.25(Q)  = 5.25

0.50Q    +  0.25Q    = 5.25

         0.75Q             = 5.25

                     =

                Q              = 7

7 quarters

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