Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 2)
2.
A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue?
Answer: Option
Explanation:
Total number of balls = (2 + 3 + 2) = 7.
Let S be the sample space.
| Then, n(S) | = Number of ways of drawing 2 balls out of 7 | |||
| = 7C2 ` | ||||
|
||||
| = 21. |
Let E = Event of drawing 2 balls, none of which is blue.
 n(E) |
= Number of ways of drawing 2 balls out of (2 + 3) balls. | |||
| = 5C2 | ||||
|
||||
| = 10. |
| P(E) = |
n(E) | = | 10 | . |
| n(S) | 21 |
Discussion:
116 comments Page 6 of 12.
Biswajit said:
5 years ago
Can anyone tell me if I subtract the probability of getting 2 blue balls i.e 2/7 from 1 then why I can't get the answer?
Please explain me.
Please explain me.
(2)
Shiba said:
1 decade ago
n(E) = Number of ways of drawing 2 balls out of (2 + 3) balls. ?
My question is why are you finding it only from 5 balls why not 7 balls.
My question is why are you finding it only from 5 balls why not 7 balls.
SRZ said:
5 years ago
P1st (not blue)= 1-P(blue) = 1-2/7 = 5/7.
P2nd(not blue)= 1-P(blue) = 1-2/6 = 4/6.
P1 and P2(not blue)=5/7 x 4/6 = 20/42 = 10/21.
P2nd(not blue)= 1-P(blue) = 1-2/6 = 4/6.
P1 and P2(not blue)=5/7 x 4/6 = 20/42 = 10/21.
(45)
Jitesh mittal said:
10 years ago
Cannot we have a different method.
It will be like 1- putting out blue balls which is 2/7.
To probability will be 1-2/7 = 5/7?
It will be like 1- putting out blue balls which is 2/7.
To probability will be 1-2/7 = 5/7?
Tenzin said:
7 years ago
It's answers is 5/7.
1 1,1 2,2 1,3 1,3 2,
Five ways that we get the ball without getting a blue ball,
So it should be 5/7.
1 1,1 2,2 1,3 1,3 2,
Five ways that we get the ball without getting a blue ball,
So it should be 5/7.
Pranav said:
1 decade ago
A bag contains 3 red, 2 green and 5 blue balls. 4 balls are drawn at random. What is the probability that 1 green ball?
Zuay said:
1 decade ago
No no no! I don't understand are we not suppose to consider probability of not obtaining blue balls here? then its 5/7.
Abic said:
9 years ago
The probability of getting blue is 2/7.
If we sub 1-2/7 the answer is 5/7 why it is inaccurate? Please explain me.
If we sub 1-2/7 the answer is 5/7 why it is inaccurate? Please explain me.
ARUN KASHYAP said:
1 decade ago
Answer is simple:
2+3+2 = 7x3(here 3 is no.of 2+3+2) = 21.
2+ 3(here 3 is no.of 2+3+2) = 5x2 = 10.
10/21.
2+3+2 = 7x3(here 3 is no.of 2+3+2) = 21.
2+ 3(here 3 is no.of 2+3+2) = 5x2 = 10.
10/21.
Sisis said:
8 years ago
The Probability of picking 1st ball is 5/7 and second is 4/6 final probability is the product 20/42=10/21.
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