In order to conduct an experiment,subjects are randomly selected from a group ofsubjects. How many different groups ofsubjects are possible?

The number of possible different groups is

nothing.

Type a whole number.)

A realtor uses a lock box to store the keys to a house that is for sale. The access code for the lock box consists ofdigits. The first digit cannot beand the last digit must be . How many different codes are available? (Note that 0 is considered an even number.)

The number of different codes available is

nothing.

Type a whole number.)