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 4 of 11.
Kiruba said:
1 decade ago
Thanks sneha. Ans is 9/20.
Rach said:
1 decade ago
Circular board of i feet has area Pi. The area of the region containing all points which are closed to center than to periphery will be Pi/4. Hence the proportion to hit near the center is 1/4=.25. So D is the correct answer.
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?
Pinki said:
1 decade ago
How we calculate n(E) and n(S). ?
Geeta chauhan said:
1 decade ago
I cant understand the ans please explain me.
Rammu said:
1 decade ago
n(E) = number of possible events
n(S) = total number of samples
Eg. Tickets which is numbered 1 to 20 is n(S)
The possible tickets drawn which has number multiple of 3 and 5 is n(E).
n(S) = total number of samples
Eg. Tickets which is numbered 1 to 20 is n(S)
The possible tickets drawn which has number multiple of 3 and 5 is n(E).
Arun said:
1 decade ago
I can't understand.
P (e) ={3, 6, 9, 12, 15, 18, 5, 10, 20}.
We multiplying p (e) with s then we don't want to multiply s={7, 8 to 18}.
P (e) ={3, 6, 9, 12, 15, 18, 5, 10, 20}.
We multiplying p (e) with s then we don't want to multiply s={7, 8 to 18}.
Aruna said:
1 decade ago
Hi murugesh what you explained is clear. Thank you.
Sohail said:
1 decade ago
15 creates a big confusion.
Because my answer is 1/2...:(
p(3)={3,6,9,12,15,18}
p(5)={5,10,15,20}
P(3u5)=p(3)+p(5)
=6/20+4/20
=6+4/20
=10/20
=1/2
Because my answer is 1/2...:(
p(3)={3,6,9,12,15,18}
p(5)={5,10,15,20}
P(3u5)=p(3)+p(5)
=6/20+4/20
=6+4/20
=10/20
=1/2
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