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A certain bank vault contains 600 safe deposit boxes. A thie
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23 Feb 2019, 10:37
23 Feb 2019, 10:37
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80% (03:04) correct
20% (01:17) wrong based on 10 sessions
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A certain bank vault contains 600 safe deposit boxes. A thief possesses a sack containing 700 keys, only 300 of which correspond to the safe deposit boxes, with no duplicates. If the thief randomly selects a box and then a key, what is the probability that the thief will be able to open the box?
A. \(\frac{1}{1400}\)
B. \(\frac{1}{600}\)
C. \(\frac{1}{7}\)
D. \(\frac{1}{2}\)
E. \(\frac{6}{7}\)
A. \(\frac{1}{1400}\)
B. \(\frac{1}{600}\)
C. \(\frac{1}{7}\)
D. \(\frac{1}{2}\)
E. \(\frac{6}{7}\)
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Re: A certain bank vault contains 600 safe deposit boxes. A thie
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27 Feb 2019, 06:36
27 Feb 2019, 06:36
1
Carcass wrote:
A certain bank vault contains 600 safe deposit boxes. A thief possesses a sack containing 700 keys, only 300 of which correspond to the safe deposit boxes, with no duplicates. If the thief randomly selects a box and then a key, what is the probability that the thief will be able to open the box?
A. \(\frac{1}{1400}\)
B. \(\frac{1}{600}\)
C. \(\frac{1}{7}\)
D. \(\frac{1}{2}\)
E. \(\frac{6}{7}\)
A. \(\frac{1}{1400}\)
B. \(\frac{1}{600}\)
C. \(\frac{1}{7}\)
D. \(\frac{1}{2}\)
E. \(\frac{6}{7}\)
KEY CONCEPT: In order to open the box, the thief must choose a key that will actually open a box AND the thief must choose the box that matches the key.
We get: P(can open box) = P(selects a key that opens a box AND selects the box that matches the key)
= P(selects a key that opens a box) x P(selects the box that matches the key)
= 300/700 x 1/600
= 3/7 x 1/600
= 3/4200
= 1/1400
Answer: A
Cheers,
Brent
Re: A certain bank vault contains 600 safe deposit boxes. A thie
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03 Mar 2023, 10:20
03 Mar 2023, 10:20
Hello from the GRE Prep Club BumpBot!
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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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).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
