A four digit number is formed using the digits 1, 2, 3, 5 with no repetitions. Write the probability that the number is divisible by 5.

Options

A. `3//4`
B. `1//4`
C. `1//8`
D. none of these

Answer

B

Explanation

The total numer of ways in which four-figure numbers can be formed is `4! = 24`. A number is divisible by 5 if at unit's place we have 5. Therefore, unit's place can be filled in one way and the remaining 3 places can be filled with the other digits in `3!` ways. Hence, total number of number divisible by 5 is `3! = 6`. So, the required probability is `6//24 = 1//4`.