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Two-similar-boxes-B-i-i-1-2-contain-i-1-red-and-5-i-1-black-balls-One-box-is-chosen-at-random-and-two-balls-are-drawn-randomly-what-is-the-probability-that-both-balls-are-of-different-colours-




Question Number 12306 by Gaurav3651 last updated on 18/Apr/17
Two similar boxes B_i  (i=1,2)contain  (i+1)red and (5−i−1) black balls.  One box is chosen at random and  two balls are drawn randomly.  what is the probability that both  balls are of different colours?  (a)  1/2  (b)  3/10  (c)  2/5  (d)  3/5
TwosimilarboxesBi(i=1,2)contain(i+1)redand(5i1)blackballs.Oneboxischosenatrandomandtwoballsaredrawnrandomly.whatistheprobabilitythatbothballsareofdifferentcolours?(a)1/2(b)3/10(c)2/5(d)3/5
Answered by mrW1 last updated on 19/Apr/17
1×((2×3)/(10))=(3/5)  ⇒(d)
1×2×310=35(d)
Commented by Gaurav3651 last updated on 19/Apr/17
Sir can you please explain the  solution.
Sircanyoupleaseexplainthesolution.
Commented by mrW1 last updated on 19/Apr/17
The answer should be 1× (6/(10))=(3/5), since  it makes no difference which box is  choosen.  5 balls in each box, 3 balls in colour A  and 2 balls in colour B.    possibilities to take 2 from 5 balls:   C(5,2)=10  possibilities to take 2 balls in different colours:   2×3=6    ⇒1×(6/(10))=(3/5)
Theanswershouldbe1×610=35,sinceitmakesnodifferencewhichboxischoosen.5ballsineachbox,3ballsincolourAand2ballsincolourB.possibilitiestotake2from5balls:C(5,2)=10possibilitiestotake2ballsindifferentcolours:2×3=61×610=35
Commented by Gaurav3651 last updated on 19/Apr/17
Thanks a lot sir
Thanksalotsir

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