TCS
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Numerical Ability
Probability
lottery balls are numbered and colored balls. in the famous lotto, six numbered balls are drawn at random from 49 balls. In each ticket one needs to guess the six numbers that would be drawn.
an urn contains m white and n black balls. a ball is drawn at random and is put back in to the urn along with k additional balls of the same color as that of the ball drawn. A ball is again drawn at random. probability of drawing a white ball now:
1) does not depend on k
2) cant be determined
3) decreases with k
4) increases with k
Read Solution (Total 18)
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- does not depend on k
- 10 years agoHelpfull: Yes(15) No(2)
- i took tcs open seame and right answer is deos not depend on k.Can anyone please tell why this is the right solution?
- 10 years agoHelpfull: Yes(7) No(5)
- cannot be determined.
- 10 years agoHelpfull: Yes(4) No(3)
- what is the right ans
- 10 years agoHelpfull: Yes(4) No(1)
- Cannot be determined because we are not sure about which ball was picked in the first attempt
- 10 years agoHelpfull: Yes(2) No(3)
- Let W1 (B1) be the event that a white (a black) ball is drawn in the first draw and let W be the event that a white ball is drawn in the second draw. Then
P (W) = P (B1). P (W| B1) + P (W1). P (W| W1)
= n/m + n. m/m + n + k + m/m + n. m + k/m + n + k
= m(n + m + k)/(m + n) (m + n + k) = m/m + n - 9 years agoHelpfull: Yes(2) No(1)
- ans is 4.
Since additional balls are but back into the urn so the probability of getting a same color (whiite) increases with k. - 10 years agoHelpfull: Yes(1) No(6)
- cannot be determined is given as wrong solution in openseesame test.which is the right solution?
- 10 years agoHelpfull: Yes(1) No(1)
- gyatribadlani@gmail.com
- 10 years agoHelpfull: Yes(1) No(0)
- decreases with k
- 10 years agoHelpfull: Yes(0) No(8)
- Ans:4
If the k additional balls of a same colour are drawn it depends upon the ball drawn at random.For eg if the number 6 (white ball) is drawn that total number is added to the urn....
increases by k - 10 years agoHelpfull: Yes(0) No(2)
- increases with k
(as the ball increases automatically based on selection) - 10 years agoHelpfull: Yes(0) No(2)
- Take an example of 3 whilte balls and 2 black balls
If K picks a white ball then the number of white balls will be 2
And it credits an addition ball along with the ball that is taken into the urn.
So the number of white balls in the urn will be 5.
The probability of picking an white ball again purely relies on the value of K. - 10 years agoHelpfull: Yes(0) No(0)
- cant be determine.
- 10 years agoHelpfull: Yes(0) No(0)
- i think answer provided on tcs sesame is wrong...it should be cant be determined
- 10 years agoHelpfull: Yes(0) No(1)
- Dear admin! Can U plz upload the soln of this qn?
- 9 years agoHelpfull: Yes(0) No(0)
- THE CORRECT ANSWER IS "CANT BE DETERMINED"
- 9 years agoHelpfull: Yes(0) No(0)
- m white balls and n black balls so in first time probability of white ball m/n+m.
probability of black ball n/n+m.
second time probability of white ball if first time ball was white (m+k)/(m+n+k)
if first time ball was black then probability of white ball m/(m+n+k)
so final probability for white ball ((m+k)/(m+n+k) + m/(m+n+k))=(2m+k)/(m+n+k)
now subtract k from both and the resultant will be free from k - 6 years agoHelpfull: Yes(0) No(0)
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