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.
Neeta said:
1 decade ago
Can anybody explain me how to solve 52C2 ? or such other examples like 7C2, 13C1 etc.
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)!
Kavitha said:
1 decade ago
Why can't it be (13C1 + 13C1) I am getting confused where 2 multiply and where 2 add can any one help me.
Khetesh said:
1 decade ago
Actually answer 13/102 is correct.
We draw 2 card:
Possibility of one heart and one spade = (possibility of first spade and second heart) + (possibility of first heart and second spade).
= (13/52)*(13/51) + (13/52)*(13/51).
= 13*13*2/52*51.
= 13/102.
We draw 2 card:
Possibility of one heart and one spade = (possibility of first spade and second heart) + (possibility of first heart and second spade).
= (13/52)*(13/51) + (13/52)*(13/51).
= 13*13*2/52*51.
= 13/102.
Jayalekshshmi s said:
1 decade ago
Number of hearts and spades in a deck of cards is 26. Am I right?
Vinay said:
1 decade ago
Probability of A and B = P(a) * P(b).
Probability of A or B = P(a) + P(b).
So, 13/204 is correct, no ?
Probability of A or B = P(a) + P(b).
So, 13/204 is correct, no ?
Sulagna said:
1 decade ago
If we are supposed to multiply 13/204 into 2, because w are considering 2 events= 1st spade 2nd heart and 2nd heart, 1st spade, then in the coloured marbles question, why don't we apply the same logic?
Dhruvil said:
1 decade ago
Probability = (13+13)/(52*51) = 26/(52*51) = 1/102.
As there are 13 spade cards and 13 heart cards in each pack of 52 cards.
As there are 13 spade cards and 13 heart cards in each pack of 52 cards.
Priya said:
1 decade ago
Why can't it be 26C2/52C2?
Shekhar said:
1 decade ago
Why can't this be done ?
26P2/52C2 ?
Can anyone please give me a proper explanation.
26P2/52C2 ?
Can anyone please give me a proper explanation.
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