An urn contains g green marbles and b blue marbles. If 3 green marbles and 5 blue marbles are added, and then one...

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An urn contains g green marbles and b blue marbles. If 3 green marbles and 5 blue marbles are added, and then one...

by AAPL » Sat Mar 27, 2021 4:21 pm

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Veritas Prep

An urn contains g green marbles and b blue marbles. If 3 green marbles and 5 blue marbles are added, and then one marble is selected at random from the urn, what is the probability that a blue marble will be drawn?

A. b/(b+g)
B. (b+5)/(g+3)
C. (b+5)/(b+g+8)
D. (b+5)/(b+g+3)
E. b/(b+g+5)

OA C

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Re: An urn contains g green marbles and b blue marbles. If 3 green marbles and 5 blue marbles are added, and then one...

by [email protected] » Thu Apr 15, 2021 10:36 am
AAPL wrote:
Sat Mar 27, 2021 4:21 pm
Veritas Prep

An urn contains g green marbles and b blue marbles. If 3 green marbles and 5 blue marbles are added, and then one marble is selected at random from the urn, what is the probability that a blue marble will be drawn?

A. b/(b+g)
B. (b+5)/(g+3)
C. (b+5)/(b+g+8)
D. (b+5)/(b+g+3)
E. b/(b+g+5)

OA C
Solution:

After 3 green marbles and 5 blue marbles are added, the total number of marbles in the urn is g + b + 3 + 5 = b + g + 8, and the number of blue marbles in the urn is b + 5. Therefore, the probability that a blue marble will be drawn is (b + 5) / (b + g + 8).