11th commerce about maths

Question

Digits are as 0,1,2,3,4,5,6,7,8 make 4 digit number which is divisible by 5. When reputation is not allowed 

Answer 1

First digit: 9 (cannot be zero)

Second digit: 10

Third digit: 10

Fourth digit: 2 (only 0 or 5)

 

9 * 10 * 10 * 2

Answer 2

The divisibility test for 5 is if the number ends in either a 0 or a 5. So the last digit can only be one of these two choices. The first digit can therefore be one of 8 remaining choices, second digit - 7 choices, and third digit - 6 choices. So the permutations can be found by multiplying 2*8*7*6.