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 4 of 13.
Javeed said:
6 years ago
In coins, we have 2 sides so 2, and how many coins they gave in the question is 3 so 2^3 = 8.
And the number HH is 7 so 7/8 is answer.
And the number HH is 7 so 7/8 is answer.
Manan said:
1 decade ago
Can't it be like this:
Probability of all events = 3 heads, 2 heads, 1 head, 0 heads.
Hence n(s) = 4.
n(e) = 3.
Probability = 3/4.
Probability of all events = 3 heads, 2 heads, 1 head, 0 heads.
Hence n(s) = 4.
n(e) = 3.
Probability = 3/4.
Arpan said:
1 decade ago
Abhijeet that's not the way to do this prob. You got it totally wrong. But your answer is matching. Have a look at Sundar's answer.
Subhsubh said:
1 decade ago
P(2 heads)= Total favourable events divided by total events. Favourable are only 2 so then why would we take 7 on the numerator ?
Puttz said:
1 decade ago
Unbiased coins means a coin having head and tail whereas a biased coin means having two heads or two tails respectively.
(1)
Aman Gupta said:
6 years ago
At most two head means that 2 or more than 2 heads are accepted but no coins are not haed or one head are not accepted.
Namgay said:
10 years ago
We know there are 8 combinations but What is the trick to get the combinations when we toss three coins like HHH TTH?
Madhuchanti said:
1 decade ago
Because of,
Sample space is n(S)=8 this is we are tossing the coins,
n(E)=7.
So probability is n(E)/n(S) = 7/8.
Sample space is n(S)=8 this is we are tossing the coins,
n(E)=7.
So probability is n(E)/n(S) = 7/8.
Saurabh patel said:
1 decade ago
If the leatter of the word LUCKNOW are randomly arrenged, find the proabibility of always having the word NOW.
Shah Rukh said:
9 years ago
Biased means neither head nor tail.
Unbiased means opposite to biased. i.e It will be in perfect outcomes.
Unbiased means opposite to biased. i.e It will be in perfect outcomes.
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