Question

How many 3 digit number can be formed by 0, 2, 5, 3, 7 which is divisible by 5 and none of the digit is repeated?

Answer 1

Answer:

36 is the right answer

Step-by-step explanation:

To be divisible by 5 unit digit of number should be either 5 or 0

We have total 6 digits out of which we cannot have 0 at the hundred’s place (else it will become a 2 digit number)

Unit place is filled with 5

a. Tens place can be filled with 0

Hundreds place can now be filled with (2, 3, 6, 7). We have 4 ways

So we have 1*1*4

b. Tens place can be filled with any of the digits (2, 3, 6, 7). We have 4 ways

Hundreds place can now be filled with remaining of 3 digits. We have 3 ways

So we have 1*4*3

Unit place is filled with 0

Tens place can be filled with any of the digits (2, 3, 5, 6, 7). We have 5 ways

Hundreds place can now be filled with remaining of 3 digits. We have 4 ways

So we have 1*5*4

So Total number of ways = 1*1*4 + 1*4*3 + 1*5*4 = 36