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 7 of 11.
Nikhil Merwade said:
1 decade ago
Why can't we use the formula of nCr...??...
1 ticket can be selected from 20 tickets in 20C1 ways.
Ticket removed is a multiple of 3 or 5 will be 20C6 * 20C4
Answer will be (20C6 * 20C4)/20C1...
Why can't this be proper method?
1 ticket can be selected from 20 tickets in 20C1 ways.
Ticket removed is a multiple of 3 or 5 will be 20C6 * 20C4
Answer will be (20C6 * 20C4)/20C1...
Why can't this be proper method?
Aarti Gosavi said:
1 decade ago
There are three drawers in a table. One drawer contains two gold coins another drawer contains two silver coins and third drawer contains one silver and one gold coin. One of the drawers is pulled out and a coin is taken out. It turns out to be a silver. What is probability of drawing a gold coin if one of the other two drawers is pulled out next and one of the coin in it is drawn at random?
Santosh said:
1 decade ago
Yah by using P(AUB)formula we can calculate this, So no doubt persists-P(A)=6/20, P(B)=4/20,and P(A^B)=1/20(since 15 common for 3,5),
Finally answer is 6/20+4/20-1/20 = 9/20.
Finally answer is 6/20+4/20-1/20 = 9/20.
Keerthi said:
1 decade ago
Here he said 3 or 5 but not 3&5 so answer will be 1\2.
Since or means we should add &and means multiply.
Since or means we should add &and means multiply.
Mosca said:
1 decade ago
Everyone is wrong. The answer is D: 9/20.
I am the best at maths see. This is because it is out of 20 and the multiplier of 3 and 5 is 9.
You see? So, it has to be 9/20.
I am the best at maths see. This is because it is out of 20 and the multiplier of 3 and 5 is 9.
You see? So, it has to be 9/20.
Shakthi said:
1 decade ago
Where this 5 gone in the event?
Sagar Valecha Soni said:
1 decade ago
Ya 9/20 is correct I am agree from this answer.
Garima said:
10 years ago
According to me the answer should be 1/2.
Multiples of 3 and 5. (1, 3, 5, 6, 9, 10, 12, 15, 18, 20).
Please let me know where am I wrong?
Multiples of 3 and 5. (1, 3, 5, 6, 9, 10, 12, 15, 18, 20).
Please let me know where am I wrong?
Divya said:
10 years ago
How to cal multiple of larger number?
Can any one give a answer for this?
Ex: Same question number is 1-300.
Can any one give a answer for this?
Ex: Same question number is 1-300.
Samuel said:
10 years ago
@Divya.
Factorize or divide it.
Factorize or divide it.
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