Tickets numbered 1 to 20 are mixed up and then a ticked is drawn at random. What is the probability that the ticket drawn bears a number which is a multiple of 3?	Choose the correct choice.
A) 3 / 10  B) 3 / 20  C) 2 / 5  D) 1 / 2  E) 1 / 3

Rationale: s = { 1 , 23 , … . 20 } e = { 3 , 6 , 912 , 1518 } p ( e ) = 6 / 20 = 3 / 10 option a
Answer: A