Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 5)
5.
Three unbiased coins are tossed. What is the probability of getting at most two heads?
Answer: Option
Explanation:
Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH}
Let E = event of getting at most two heads.
Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.
 P(E) = |
n(E) | = | 7 | . |
| n(S) | 8 |
Discussion:
121 comments Page 12 of 13.
Shobha said:
2 years ago
I don't understand this logic - Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.
As this question says event of getting at most two heads.
It should be these combinations- THH, HTH, HHT, HHH.
Please, someone, explain.
As this question says event of getting at most two heads.
It should be these combinations- THH, HTH, HHT, HHH.
Please, someone, explain.
(24)
Jiju said:
2 years ago
At most means maximum, that means no more than 2 heads, so the events include TTT, HTT, HHT, THH, TTH, HTH, and THT.
HHH is not right because it's more than two heads, at most means not more than two so it includes 0 heads, 1 head, 2 heads.
HHH is not right because it's more than two heads, at most means not more than two so it includes 0 heads, 1 head, 2 heads.
(44)
Asmi said:
2 years ago
At most means not more than 2 heads.
And at least means more than 2 heads.
And at least means more than 2 heads.
(24)
Chelsia said:
2 years ago
We can get quickly the number of events like 2 to the Power of (number of coins).
I.e 2'3=> 8.
I.e 2'3=> 8.
(7)
Manisha Yadav said:
2 years ago
The right answer should be 3/8.
(15)
Sowmya said:
1 year ago
The Answer should be 3/8.
(4)
Ismail said:
1 year ago
"At most 2 head" means a maximum 2 no. of heads that is there can be 0 heads,1 head or 2 heads.
So, TTT, TTH, THT, THH, HTT, HHT, HTH have at most 2 heads.
So, n(E)=7 & n(S)= 8 ---> n(E)/n(S) = 7/8.
So, TTT, TTH, THT, THH, HTT, HHT, HTH have at most 2 heads.
So, n(E)=7 & n(S)= 8 ---> n(E)/n(S) = 7/8.
(14)
Ragini said:
1 year ago
The right Answer is 3/8.
(12)
Reena said:
1 year ago
At most 2 heads means it cannot be more than 2. It can be zero or 1 or 2 but not 3. And there is only one case that have 3 (HHH). So probability is 7/8.
(39)
Chinmay Gawane said:
10 months ago
3/8 is the right answer.
(19)
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