Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 1)
1.
Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5?
Answer: Option
Explanation:
Here, S = {1, 2, 3, 4, ...., 19, 20}.
Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}.
 P(E) = |
n(E) | = | 9 | . |
| n(S) | 20 |
Discussion:
107 comments Page 8 of 11.
Nithya Arun said:
8 years ago
How can we calculate the same problem with big numbers? i.e if tickets numbered 1-200.
Shailendra rathore said:
9 years ago
9/20 is the right answer, and thanks for explaining the answer in different ways.
Ganapathithanuja said:
2 years ago
If 15 is there then the answer is 1/2.
Am I right? Anyone, please explain.
Am I right? Anyone, please explain.
(40)
Prawesh Pradhan said:
9 years ago
P(A) + P(B) - P(A and B).
6 + 4 - 1 = 9.
P(E) = n(E)/n(S).
P(E) = 9/20.
6 + 4 - 1 = 9.
P(E) = n(E)/n(S).
P(E) = 9/20.
Kavya said:
6 years ago
@Uday,
15 is repeated.
And 5 is missing.
Anyway, the answer is correct.
15 is repeated.
And 5 is missing.
Anyway, the answer is correct.
(5)
Rahul said:
1 decade ago
@rach.
Hai rach I didn't get you. Can you please explain clearly.
Hai rach I didn't get you. Can you please explain clearly.
Sreejith said:
1 decade ago
Hello Rach,
How did you get that as pi/4?
Or anybody else knows?
How did you get that as pi/4?
Or anybody else knows?
Dabir Masood said:
9 years ago
Yes I too agree that 1/2 is the correct answer for this question.
(1)
ABHISEK MUKHERJEE said:
1 decade ago
Use just simple probability formula,
P(A+B) = P(A)+P(B)-P(AB).
P(A+B) = P(A)+P(B)-P(AB).
Shraddha said:
7 years ago
But why is the number 5 not considered? 5 is a multiple of 5!
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