Mathmetics
ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams
Q11. |
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| 1) | 1/24 | 2) | 21/46 |
| 3) | 1/48 | 4) | 24/117 |
| 5) | None of these | ||
Answer : 21/46
Explanation :
Explanation :
Let S be the sample space and E be the event of selecting 1 girl and 2 boys.
Then, n(S) = 25C3 = Number ways of selecting 3 students out of 25
= (25 x 24 x 23) / (3 x 2 x 1) = 2300.
n(E) = (10C1 x 15C2)
= 10 x (15 x 14) /(2 x 1) = 1050.
So, P(E) = n(E) / n(S) =1050 / 2300 =21/46
View AnswerQ12. |
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| 1) | 1/4 | 2) | 3/4 |
| 3) | 7/8 | 4) | 1/36 |
| 5) | None of these | ||
Answer : 7/8
Explanation :
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}.
So, P(E) = n(E) / n(S) =7 /8 .
View AnswerQ13. |
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| 1) | 1/6 | 2) | 1/8 |
| 3) | 1/9 | 4) | 1/12 |
| 5) | None of these | ||
Answer : 1/9
Explanation :
Explanation :
In two throws of a die, n(S) = (6 x 6) = 36.
Let E = event of getting a sum ={(3, 6), (4, 5), (5, 4), (6, 3)}.
So,P(E) = n(E) / n(S) = 4 /36 =1/9.
View Answer