NCERT Class XII Mathematics Chapter - - Solutions
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Question : 30
Total: 101
Two balls are drawn at random with replacement from a box containing 10 black and 8 red balls. Find the probability that
(i) both balls are red.
(ii) first ball is black and second is red.
(iii) one of them is black and other is red.
(i) both balls are red.
(ii) first ball is black and second is red.
(iii) one of them is black and other is red.
Solution:
Total no. of balls = 18
(i) Let E : When both balls are red with replacement, thenP ( E ) =
×
=
(ii) Let E : When first ball is black & second is red, then
P ( E ) =
×
=
(iii) Let E : When one of them is black and other red, then
P ( E ) =
×
+
×
=
(i) Let E : When both balls are red with replacement, then
(ii) Let E : When first ball is black & second is red, then
(iii) Let E : When one of them is black and other red, then
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