Question

Four-digit numerical codes are issued for an ATM. If no integer can be repeated in a code, how many different codes can be formed using only odd integers?

Answer 1

The answer is "120".

Explanation:

The assuming numbers:

`0, 1,2,3,4,5,6,7,8,9`

The odd number are=
`1,3,5,7,9`

Now we have four places:

In the first place we have 5 option

In second place we have 4 option

In third place, we have 3 option

In fourth place, we have 2 option

So, the value is
`5 * 4 * 3* 2 * 1= 120`

So, we have 120 different codes, which form the code.