Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 3)
3.
In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green?
Answer: Option
Explanation:
Total number of balls = (8 + 7 + 6) = 21.
| Let E | = event that the ball drawn is neither red nor green |
| = event that the ball drawn is blue. |
n(E) = 7.
| P(E) = |
n(E) | = | 7 | = | 1 | . |
| n(S) | 21 | 3 |
Discussion:
36 comments Page 4 of 4.
Ravindra said:
7 years ago
How can p(e) =7?
Because neither red nor green clearly means its blue.
Because neither red nor green clearly means its blue.
(1)
Rohit said:
7 years ago
How n(E) =7?
Shiv said:
4 years ago
Neither red''ï¸ nor green'' means (avoiding red and green) so we left out with blue means the one ball we have to pick up should be blue colour ball so.
P(E) = 7/21 = 1/3.
P(E) = 7/21 = 1/3.
(1)
Chris said:
4 years ago
@All.
Here, You can solve it in two ways.
Method 1:
Total number of balls = 7+8+6= 21.
Neither red nor green, that means it is blue,
Number of blue = 7,
Probability of blue = number of blue balls÷ total number of balls.
Probability of blue balls= 7/ 21.
1/3.
Method 2:
Total number of balls = 21.
Number of Red = 8.
Prob of selecting red = 8/21 or.
Number of Green = 6.
Prob of selecting green = 6/21 or 2/7.
Neither Red nor Green = 1-(prob of red+ prob of green).
1 - (8/21 + 6/21).
1 - 14/21 = 7/21 or 1/3.
Here, You can solve it in two ways.
Method 1:
Total number of balls = 7+8+6= 21.
Neither red nor green, that means it is blue,
Number of blue = 7,
Probability of blue = number of blue balls÷ total number of balls.
Probability of blue balls= 7/ 21.
1/3.
Method 2:
Total number of balls = 21.
Number of Red = 8.
Prob of selecting red = 8/21 or.
Number of Green = 6.
Prob of selecting green = 6/21 or 2/7.
Neither Red nor Green = 1-(prob of red+ prob of green).
1 - (8/21 + 6/21).
1 - 14/21 = 7/21 or 1/3.
(17)
Romeo said:
3 years ago
Thanks all for explaining.
(4)
Kigele yazidi said:
2 years ago
Total number of balls = 8 + 7 + 6,
=21.
Probability not red or green= number of events/sample space.
So, 7÷21 = 1/3.
=21.
Probability not red or green= number of events/sample space.
So, 7÷21 = 1/3.
(6)
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