Question : A four figure number is formed of the figures 1, 2, 3, 5 with no repetitions. The probability that the number
(D) none of these
Answer : option (B)
The total number 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 numbers divisible by 5 is 3!=6. so the required probability is 6/24=1/4.