Question

Q3 Write all possible 3-digit numbers using the digits 6.0.4 when
() Repetition of digits is not allowed
(ii) Repetition of digits is allowed​

Answer 1

There are three digits to use in a three digit number. So each will use all three of 0, 4, 6

The first digit can’t be 0 (or it will be a two-digit number) so it must start 6 or 4, and the other two digits are then 0/4 or 0/6, and can be in either order (two possibilities).

S0 there are 2 x 2 possibilities

640

604

460

406

So, there are 4 such numbers