Arithmetic Ability
 Probability

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Q.

Tickets are numbered from 1 to 18 are mixed up together and then 9 tickets are drawn at random. Find the probability that the ticket has a number, which is a multiple of 2 or 3

View Answer

Correct choice: C

Explanation:

S = { 1, 2, 3, 4, .....18 } => n(S) = 18 E1 = {2, 4, 6, 8, 10, 12, 14, 16, 18} => n(E1) = 9 E2 = {3, 6, 9, 12, 15, 18 } => n(E2) = 6 E3 =(E1∩E2)={6, 12, 18} => n(E3) = 3 ∴E=E1 ∪ E2 = E1+E2−E3 => n(E) = 9 + 6 - 3 =12 where E = { 2, 3, 4, 6, 8, 9, 10, 12, 12, 14, 15, 16, 18 } ∴P(E)=n(E)/n(S)=12/18=2/3
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