Given, a four-digit number is formed with the digits 1, 2, 3, 5 with no repetitions. There are as many numbers as there are ways of filling in 4 vacant places.
The no. of ways in which the 4 places can be filled, by multiplication principle, is 4 x 3 x 2 x 1 = 24 ways
For the Numbers divisible by 5,
the 4th place can be only filled by 1 way i.e., by 5, the 1 st place can be filled by 3 ways (since repetition is not allowed), the second place by 2 ways and the third by 1 way.
\(\therefore\) total numbers divisible by 5 = 3 x 2 x 1 x 1 = 6
P (no. divisible by 5) = \(\cfrac6{24}=\cfrac14=0.25\)
