Question

find the number of 3 digits numbers while can be formed using digits 0,2,3,4,7,9 without repeating repeating the digits?​

Answer 1

Step-by-step explanation:

ex : consider [x][y][z] as a 3 digit number

now, we have to fit 0,2,4,5,9 into these positions

[x] → can’t have 0 cuz it would turn it into a 2 digit no. , so [x] can have 4 digits only

[y] → can have all 5

[z] → can have all 5

number of 3 digit nos. ==> 4*5*5 ==> 100

Note : This is solution is when digits can repeat

Solution for non repeating digits is as followed : -

[x] → can’t have 0 cuz it would turn it into a 2 digit no. , so [x] can have 4 digits only

[y] → can have all 4

[z] → can have all 3

number of 3 digit nos. ==> 4*4*3 ==> 48