Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 4)
4.
What is the probability of getting a sum 9 from two throws of a dice?
Answer: Option
Explanation:
In two throws of a dice, n(S) = (6 x 6) = 36.
Let E = event of getting a sum ={(3, 6), (4, 5), (5, 4), (6, 3)}.
 P(E) = |
n(E) | = | 4 | = | 1 | . |
| n(S) | 36 | 9 |
Discussion:
52 comments Page 2 of 6.
Swathi said:
7 years ago
Why we should not use the permutations here?like sum 9 can appear in either (6, 3) or (3, 6) , (5, 4) or (4, 5). Why we only choose the one possibility?
(1)
Pooja gm said:
7 years ago
Why we take this case only?
(3+6)
(4+5)
(5+4)
(6+3).
This also possible;
(7+2),
(1+8),
(2+7),
(8+1),
Please explain the reason.
(3+6)
(4+5)
(5+4)
(6+3).
This also possible;
(7+2),
(1+8),
(2+7),
(8+1),
Please explain the reason.
(1)
Naimulsamad said:
9 years ago
Look in a dice there are number 1, 2, 3, 4, 5, 6.
To form as a 9 we need 6 + 5 + 4 + 3 number. Such as 5 + 4 = 9, 6 + 3 = 9 but 1 + 8 or 2 + 7 is not possible because dice do not contain the number 7, 8.
So sum up the number 6 +5 + 4 + 3 = 18 (one dice). 18 * 2 = 36 (two dice).
To form as a 9 we need 6 + 5 + 4 + 3 number. Such as 5 + 4 = 9, 6 + 3 = 9 but 1 + 8 or 2 + 7 is not possible because dice do not contain the number 7, 8.
So sum up the number 6 +5 + 4 + 3 = 18 (one dice). 18 * 2 = 36 (two dice).
(1)
Reena said:
1 decade ago
Two of a dice n(S) = 6*6 because 1 dice = 1, 2, 3, 4, 5, 6.
1 dice = 1, 2, 3, 4, 5, 6.
= 1(6)*1(6) = 36.
Let E = Event of getting a sum = {(3, 6), (4, 5), (5, 4), (6, 3)}.
= (3+6) = 9.
= (4+5) = 9.
= (5+4) = 9.
= (6+3) = 9.
As a question,
P(E) = n(E)/n(S) = 4/36 = 1/9.
1 dice = 1, 2, 3, 4, 5, 6.
= 1(6)*1(6) = 36.
Let E = Event of getting a sum = {(3, 6), (4, 5), (5, 4), (6, 3)}.
= (3+6) = 9.
= (4+5) = 9.
= (5+4) = 9.
= (6+3) = 9.
As a question,
P(E) = n(E)/n(S) = 4/36 = 1/9.
Laxmipriya said:
10 years ago
Why to do multiplication like 6*6=36? Why we can't do addition?
Like 6+6 = 12. I can't understand when to do addition and when to do multiplication.
Like 6+6 = 12. I can't understand when to do addition and when to do multiplication.
Amol Pawar said:
10 years ago
Dice has 6 faces, i.e (1, 2, 3, 4, 5, 6) in this addition of 9 occurs when (5+4 or 4+5) and (6+3 or 3+6) that means 4 ways.
In this way n(e) = 4 and n(s) = 6*6 =36.
P (e) = n(e)/n(s) = 4/36 = 1/9.
In this way n(e) = 4 and n(s) = 6*6 =36.
P (e) = n(e)/n(s) = 4/36 = 1/9.
Deepthi said:
9 years ago
By throwing 2 dies, to get a sum of 9 there are also possibilities of getting (1,8) (2,7) (3,6) (4,5) (5,4) (6,3) (7,2) (8,1) we have 8 possibilities please explain this.
Chethan said:
9 years ago
Why they took n(E)/n(S)? In some other problem, they took n(S)/n(E).
John said:
1 decade ago
Do you need to do all thus working out?
Umar said:
9 years ago
9 + 9 = 18,
=> 2/18 = 1/9.
=> 2/18 = 1/9.
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