The acces code to a house's security system consists of six digits. How many different codes are available each digit can be repeated?

151,200

This represents the multiplication of all the choices available for each of the 6 blanks and when you multiply these numbers you get : 10*9*8*7*6*5 = 90 * 56 * 30 = 151,200. This means we have 151,200 different codes possible if each digit cannot be repeated