1. A bag has 2 pink, 3 black and 2 blue balls. The balls are drawn randomly without
replacement till a blue ball is drawn. What is the probability that the first time a blue ball
appears in an odd numbered draw?
Answers
Answered by
5
Answer:
the answer must be black
Answered by
3
Step-by-step explanation:
Let's solve for black first. There is a
5
8
chance that a black marble will be chosen. A black marble is chosen without replacement. There are now 4 black marbles in a bag of 7 marbles, so there is a
4
7
chance that a black marble will be chosen. Let's now multiply the two fractions together to find our probability:
(
5
8
)
⋅
(
4
7
)
=
20
56
=
5
14
Let's now solve for white. There is a
3
8
chance that a white marble will be chosen. The marble is chosen and not replaced. There are now 2 white marbles in a bag of 7 marbles, so there is now a
2
7
chance that a white marble will be chosen. Let's multiply the two fractions together like last time:
(
3
8
)
⋅
(
2
7
)
=
6
56
=
3
28
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