Question

write the all possible 3 - digit numbers using the digits 7, 5, 1.
(Repetition not allowed )​

Answer 1

Step-by-step explanation:

Total no of digits are =3

Now, when we can fill the Units place of a 3-digits number by 3 ways i.e. we can use any of the given number to fill the unit place.

Similarly , we can fill the Tens place of a 3-digits number in 3 ways ,since the repetition of digits are allowed ,so we can use the same number as many times as we want.

And

We can fill the Hundreds place of a 3-digits number in 3 ways ,it has the same reason as incase of Tens place.

Therefore , Total no of ways to fill the 3-digits number is = 3*3*3 =27 .

So, we can make 27 different 3-digits number using these numbers 1 ,5 ,7 by arranging them in 27 different ways