Question

@perurabo
here you go
The first jar contains 4 blue and 5 red marbles; the second basket contains 3 blue and
4 red marbles. One marble is randomly extracted from the first basket and put into the second. After that, a marble is extracted from the second basket. What is the probability that this marble is blue?

A) 1/3

B) 15/36

C) 31/72

D) 4/9

Answer 1

oh, ok, sorry

Answer 2

No problem

Answer 3

You know , this is kind of easy, but since people want things spelled out to them, I'll pass

Answer 4

Among all possible scenarios there are two that suit us:

I. A blue marble is put into the second basket and then a blue marble is extracted from the second basket.
II. A red marble is put into the second basket and then a blue marble is extracted from the second basket.
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A::The probability of the first scenario which is probability that a blue marble is taken from the first basket × probability that a blue marble is then extracted from the second basket = 4/9 × 1/2 = 4/18.

B::The probability of the second scenario: probability that a red marble is taken from the first basket × probability that a blue marble is then extracted from the second basket = 5/9 × 3/8 = 15/72.
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The probability of futher first or second scenario: 4/18 + 15/72 = ???
Add them and deduce the answer :)

Answer 5

Either*

Answer 6

so that gives 31/72 ?

Answer 7

Exactly :3

Answer 8

That's correct @Eyad Good :D

Answer 9

oh, ok, thats great , ty

Answer 10

Yw :)

Answer 11

:)