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In a box there are A green balls, 3A + 6 red balls and 2 yellow ones.
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01 Oct 2021, 09:34
01 Oct 2021, 09:34
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In a box there are A green balls, 3A + 6 red balls and 2 yellow ones. If there are no other colors, what is the probability of taking out a green or a yellow ball?
A 1/5.
B 1/2.
C 1/3.
D 1/4.
E 2/3.
A 1/5.
B 1/2.
C 1/3.
D 1/4.
E 2/3.
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: In a box there are A green balls, 3A + 6 red balls and 2 yellow ones.
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01 Oct 2021, 09:55
01 Oct 2021, 09:55
1
Carcass wrote:
In a box there are A green balls, 3A + 6 red balls and 2 yellow ones. If there are no other colors, what is the probability of taking out a green or a yellow ball?
A 1/5.
B 1/2.
C 1/3.
D 1/4.
E 2/3.
A 1/5.
B 1/2.
C 1/3.
D 1/4.
E 2/3.
APPROACH #1: Assign a nice value to the value of A
If A = 1, then we have:
1 green ball
9 red balls
2 yellow balls
So, there are 12 balls altogether, and 3 of the balls are either green or yellow
So, P(selected balls is either green or yellow) = 3/12
= 1/4
Answer: D
APPROACH #2: Use algebra.
Given:
A = number of green balls
3A + 6 = number of red balls
2 = number of yellow balls
TOTAL number of balls = A + (3A + 6) + 2 = 4A + 8
Number of balls that are either green or yellow = A + 2
So, P(selected balls is either green or yellow) = (A + 2)/(4A + 8)
= (1)(A + 2)/(4)(A + 2)
= 1/4
Answer: D
Cheers.
Brent
Re: In a box there are A green balls, 3A + 6 red balls and 2 yellow ones.
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29 Aug 2025, 06:56
29 Aug 2025, 06:56
Hello from the GRE Prep Club BumpBot!
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Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
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