Discussion :: Probability
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In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
|
A.
\(\frac { 21 } { 46 }\) |
|
B.
\(\frac { 25 } { 117 }\) |
|
C.
\( \frac { 1 } { 50} \) |
|
D.
\(\frac { 3 } { 25 } \) |
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Answer : Option A
Explanation :
Let S be the sample space and E be the event of selecting 1 girl and 2 boys.
| Then, n(S) | = Number ways of selecting 3 students out of 25 |
| = 25C3 |
=\(\frac { (25*24*23) } { (3*2*1) } \)
=2300
| n(E) |
= (10C1 x 15C2) |
= [ 10 X \(\frac { (15*14) } { (2*1) }]\)
=1050
P(E) = \(\frac {n(E) } { n(S) } \)= \( \frac { 1050 } { 2300 } \)=\(\frac { 21 } { 46 }\)
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