The probability that a number selected at random from the numbers 1, 2, 3, ..., 15 is a multiple of 4, is

Multiples of 4 between 1 to 15 is: 4, 8, 12.
Number of favourable out comes = 3
Total number of possibilities = 15.
Probability that a number selected at random from the numbers is a multiple of 4 = 3/15 = 1/5