An urn contains 6 balls of which two are red and four are black. Two balls are drawn at random. Probability that they are of the different colours is
A. `(2)/(5)`
B. `(1)/(15)`
C. `(8)/(15)`
D. `(4)/(15)`
1 Answers
Talk Doctor Online in Bissoy App
A bag contains b blue balls and r red balls. If two balls are drawn at random, the probability drawing two red balls is five times the probability of
Correct Answer - A::B Let the number of red and blue balls be r and b, respectively. Then, the probability of drawing two red balls is `p_(1) = (.^(r )C_(2))/(.^(r+b)C_(2)) =...
2 Answers 1 views
A bag contains 10 different balls. Five balls are drawn simultaneously and then replaced and then seven balls are drawn. The probability that exactly
Number of ways of drawing 7 balls (second draw) = `.^(10)C_(7)` For each set of 7 balls of the second draw, 3 must be common to the set of 5...
2 Answers 3 views
An urn contains 5 red and 2 black balls. Two balls are drawn at random. X denotes the number of black balls drawn.
The urn contains 5 red and 2 black balls. If two balls are drawn from the urn, it contains either 0 or 1 or 2 black balls. X can take values 0,...
2 Answers 1 views
An urn contains 10 black and 5 white balls. Two balls are drawn from the run one after the other without replacement. What is the probability that fir
Let A nad B denote, respectively, the events that first ball drawn is black and second ball drawn in white. We have to find `P(AnnB) or P(AB).` ` P(AnnB)P(A)P(B//A)` Now,...
2 Answers 1 views
A bag contains `W` white and 3 black balls. Balls are drawn one by one without replacement till all the black balls are drawn. Then find the probabili
Procedure of drawing th balls has to end at the rth draw. So, exactly two black balls are drawn in first (r-1) draws and third black ball is drawn in...
2 Answers 1 views
An urn contains 6 white and 4 black balls. A fair die is rolled and that number of balls we chosen from the urn. Find the probability that the balls s
Let `A_(i)` denote the event that the number I appears on the dice and let E denote the event that only white balls are drawn. Then `P(A_(i))=1/6"for"i=1,2..,6` `and P(E//A_(i))=(""^(6)C_(i))/(""^(10)C_(i)),i=,2,.., 6`...
2 Answers 1 views
A bag contains 5 white and 3 black balls. Four balls are successively drawn out without replacement. What is the probability that they are alternately
Correct Answer - `1/7` Required probability `=P(WBWB)+P(BWBW)` `=P(W)P(B//W)P(W//WB)P(B//BWB)` `=5/8xx3/7xx4/6xx2/5+3/8xx5/7xx2/6xx4/5` `=(1)/(14)+(1)/(14)=1/7`
2 Answers 1 views
There are two urns `Aa n dB` . Urn `A` contains 5 red, 3 blue and 2 white balls, urn `B` contains 4 re3d, 3 blue, and 3 white balls. An urn is chosen
Correct Answer - D Let A nad B, respectively, be the events that urn A and urn B are selected.Let R be the event that the selected ball is red. Since...
2 Answers 1 views
An urn contains three red balls and n white balls. Mr. A draws two balls together from the urn. The probability that they have the same color is `1//2
Correct Answer - D In the first case, the urn contains 3 red and n white balls. The probability that color of both the balls matches is `(""^(3)C_(2)+""^(n)C_(2))/(""^(n+3)C_(2))=1/2` `or(6+n(n-1))/((n+3)(n+2))=1/2` `or2(n^(2)-n+6)=n^(2)+5n+6` `orn^(2)-7n+6=0`...
2 Answers 1 views
A box `B_(1)` contains 1 white ball, 3 red balls, and 2 black balls. An- other box `B_(2)` contains 2 white balls, 3 red balls. A third box `B_(3)` co
Correct Answer - A P (required) = P (all are white) + P (all are red) + P (all are black) `=1/6xx2/9xx3/12+3/6xx3/9xx4/12+2/6xx4/9xx2/12=6/648+36/648+40/648=82/648`
2 Answers 1 views