Ma and Pa were wrong and the banker was right . Ma and Pa claimed that 5 could go into 25 14 times  no  that is  incorrect . Banker claimed 5 goes in to 25  5 times that is correct.

I say  if you add 5 5 times you will get 25 . If you multiply 5 times 5 it = 25 divided by 5 is 5 . That proves the answer