How many different BCD numbers can be stored in a register o

How many different BCD numbers can be stored in a register of 12 switches? (Assume two-position, on/off, switches.)

Solution

1 Switch is equivalent to 1 bit

So total 12 bits are there

Make 3 group of 12 bit . Means each group contain 4 bit.

in any group max 10 numbers can be stored

So 10*10*10 different BCD numbers can be stored in this 12 Switches.

hence answer is 10^3