Aptitude - Probability - Discussion
Discussion Forum : Probability - General Questions (Q.No. 13)
13.
Two cards are drawn together from a pack of 52 cards. The probability that one is a spade and one is a heart, is:
Answer: Option
Explanation:
Let S be the sample space.
| Then, n(S) = 52C2 = | (52 x 51) | = 1326. |
| (2 x 1) |
Let E = event of getting 1 spade and 1 heart.
 n(E) |
= number of ways of choosing 1 spade out of 13 and 1 heart out of 13 |
| = (13C1 x 13C1) | |
| = (13 x 13) | |
| = 169. |
| P(E) = |
n(E) | = | 169 | = | 13 | . |
| n(S) | 1326 | 102 |
Discussion:
42 comments Page 4 of 5.
Karim said:
1 decade ago
@Ali, your answer is correct.
The answer should in fact be 13/204 and not 13/102.
You have 13/52 for the first card and for the second it's 13/51.
Multiple together you get 13/204.
The answer should in fact be 13/204 and not 13/102.
You have 13/52 for the first card and for the second it's 13/51.
Multiple together you get 13/204.
(1)
Ali said:
1 decade ago
But 13/52 * 13/51 is not equal to 13/102, but rather 13/204.
Irfan said:
1 decade ago
52C2 = 52/2*51/1 i.e. 1326 Answer.
or
nCr = n!/(r!)(n - r)!
or
nCr = n!/(r!)(n - r)!
Neeta said:
1 decade ago
Can anybody explain me how to solve 52C2 ? or such other examples like 7C2, 13C1 etc.
Amol said:
1 decade ago
Thanks Probability
Santosh said:
1 decade ago
Here actually we discussed earlier as both are same combination we add other wise multiply. So clarify that doubt. I understood this problem but add and multiply explain.
Xyz said:
1 decade ago
@ kavita:
in case of "AND" we have to "multiply"
& in case of "OR" we have to "Add"
in case of "AND" we have to "multiply"
& in case of "OR" we have to "Add"
Swetha said:
1 decade ago
@kavitha.
In this question, we have to find propability for taking 2 cards one is spade and another one is heart. If and comes, we should multiply likewise if or is given, then we should add.
In this question, we have to find propability for taking 2 cards one is spade and another one is heart. If and comes, we should multiply likewise if or is given, then we should add.
Mdk said:
1 decade ago
Thanks parikshit.
Probablity said:
1 decade ago
1st card is a spade = 13/52 AND
2nd card is a heart = 13/51
therefore 13/52 x 13/51 ... (1)
OR
1st card is a heart = 13/52 AND
2nd card is a spade = 13/51
therefore 13/52 x 13/51 ... (2)
Adding 1 & 2 we get 13/102
2nd card is a heart = 13/51
therefore 13/52 x 13/51 ... (1)
OR
1st card is a heart = 13/52 AND
2nd card is a spade = 13/51
therefore 13/52 x 13/51 ... (2)
Adding 1 & 2 we get 13/102
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