Question

A 3 digit number is to be formed using the digits.
from o to 9. how many such mumbers can be formed
if the repetition of digits it
i allowed. ii] not allowed.​

Answer 1

Step-by-step explanation:

1) If repetition is allowed.

see, we have 3 spaces .

in first space we can't put zero as it will then become a 2 digit number.

so for first space we have 9 values (1-9)

for other two we can we 10 values (0-10)

Ans= 9 ✖️ 10 ✖️ 10

900.

2)

if repetition is not allowed.

then

answer should be

9 ✖️9 multiply✖️8=648