Question

20 tickets, on which numbers 1 to 20 are written, are mixed thoroughly and then a ticket is drawn at random out of them. Find the probability that the number on the drawn ticket is a multiple of 3 or 7.

Answer 1

You're Answer

______

See,
Total number of outcomes = 20 
Possible outcomes = 3, 6, 7, 9, 12, 14, 15 and 18 
∴ Number of favourable outcomes = 8 

Probability = Number   of   favourable  outcomes Total   number   of   outcomes 
∴   Probability   that   the   number   on   the  drawn   ticket   is   a   multiple   of   3   or   7 = 820 = 2 5

Answer 2

Answer


Here, S = {1, 2, 3, 4, ...., 19, 20}.

Let E = event of getting a multiple of 3 or 7 = {3, 6 , 9, 12, 15, 18, 7,14}.

P(E) = n(E)/n(S) = 8/20

P(E) = 2/5.


Thank you