13. A bag has 20 white balls, 10 red and 15 black balls
balls. Find the fraction of
(a) Red balls
(b) Black balls
(c) White balls.
Answers
Answered by
5
a) 10/45 = 2/9
b) 15/45 = 1/3
c) 20/45 = 4/9
Answered by
2
Answer:
Let A: be the event that first ball is white
And B: be the event that second ball is black
P(A)=
Total number of balls
Number of white balls
=
25
10
=
5
2
P(B)=
Total number of balls left
Number of black balls
=
24
15
=
8
5
{24 because 1 ball was taken out and not replaced}
Hence the probability that first is white and second is black =
5
2
×
8
5
=
4
1
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