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 6 of 11.
Ketan said:
1 decade ago
p(3) = {3,6,9,12,15,18}.
p(5) = {5,10,15,20}.
P(3u5) = p(3)+p(5).
I don't understand how it's come
= 6/20+4/20 ?
p(5) = {5,10,15,20}.
P(3u5) = p(3)+p(5).
I don't understand how it's come
= 6/20+4/20 ?
Rajini said:
1 decade ago
Please anyone help me for solving this problem:
Condition 1: Whenever a white ball + black ball is taken out a black ball is placed in.
Condition 2: Whenever 2 black balls are taken out one white ball is placed in.
Condition 3: Whenever 2 white balls are taken out one white ball is placed inside.
Suppose user gives this input:
Black balls: 5.
White balls: 4.
Output should be any of these:
White ball/black ball/undetermined.
Condition 1: Whenever a white ball + black ball is taken out a black ball is placed in.
Condition 2: Whenever 2 black balls are taken out one white ball is placed in.
Condition 3: Whenever 2 white balls are taken out one white ball is placed inside.
Suppose user gives this input:
Black balls: 5.
White balls: 4.
Output should be any of these:
White ball/black ball/undetermined.
Ravi said:
1 decade ago
ANS IS 9/20.
PROBABILITY = NUMBER OF FAVORABLE EVENTS/NUMBER OF TOTAL EVENTS.
Events of greeting multiple 3 of 5= 3, 6, 9, 12, 15, 18, 5, 10, 20.
P(E) = P(F)/P(E).
P(E) = 9/20.
PROBABILITY = NUMBER OF FAVORABLE EVENTS/NUMBER OF TOTAL EVENTS.
Events of greeting multiple 3 of 5= 3, 6, 9, 12, 15, 18, 5, 10, 20.
P(E) = P(F)/P(E).
P(E) = 9/20.
Adhamki dileep kumar said:
1 decade ago
Sample space p(s) = 20c1 = 20.
Events occurred p(e) = (3,6,9,12,15,18,5,10,15,20) = 10.
= (3,6,9,12,15,18,5,10,20)=9
Probability = p(e)/p(s).
= 9/20.
Events occurred p(e) = (3,6,9,12,15,18,5,10,15,20) = 10.
= (3,6,9,12,15,18,5,10,20)=9
Probability = p(e)/p(s).
= 9/20.
Sharada said:
1 decade ago
15 also should come in the list right?
Niha said:
1 decade ago
Yes, 9/20 is the correct answer.
Goutam said:
1 decade ago
Yes answer is 9/20 because if we consider two event A & B which are multiple of 3 and 5 respectively then the required event is P(AuB)= P(A)+ P(B)-p(AB) = 6/20+4/20-1/20 = 9/20.
Rupali said:
1 decade ago
Hi all.
Can anyone explain how 1/20 come?
Can anyone explain how 1/20 come?
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).
Saiful Islam said:
1 decade ago
Actually, I don't understand your explanation boss. Please explain elaborately. How can it will be 9/20?
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