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GRE Prep Club Team Member
Joined: 20 Feb 2017
Posts: 2506
Given Kudos: 1055
GPA: 3.39
The probability that a visitor at the mall buys a pack of candy is 30%
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26 Jul 2022, 02:04
26 Jul 2022, 02:04
Expert Reply
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Question Stats:
37% (01:21) correct
62% (02:04) wrong based on 8 sessions
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The probability that a visitor at the mall buys a pack of candy is 30%. If three visitors come to the mall today, what is the probability that exactly two visitors will buy a pack of candy?
A) 0.343
B) 0.147
C) 0.189
D) 0.063
E) 0.027
A) 0.343
B) 0.147
C) 0.189
D) 0.063
E) 0.027
Re: The probability that a visitor at the mall buys a pack of candy is 30%
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26 Jul 2022, 12:44
26 Jul 2022, 12:44
2
The answer is D:
Out of three people 2 buy candy pack. The 3rd person don't.
Buy = 0.3
Not buy = 0.7
Then ---》 2*(0.3)*0.7 =0.063.
Posted from my mobile device
Out of three people 2 buy candy pack. The 3rd person don't.
Buy = 0.3
Not buy = 0.7
Then ---》 2*(0.3)*0.7 =0.063.
Posted from my mobile device
Re: The probability that a visitor at the mall buys a pack of candy is 30%
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29 Nov 2022, 06:37
29 Nov 2022, 06:37
1
Jafar10 wrote:
The answer is D:
Out of three people 2 buy candy pack. The 3rd person don't.
Buy = 0.3
Not buy = 0.7
Then ---》 2*(0.3)*0.7 =0.063.
Posted from my mobile device
Out of three people 2 buy candy pack. The 3rd person don't.
Buy = 0.3
Not buy = 0.7
Then ---》 2*(0.3)*0.7 =0.063.
Posted from my mobile device
Actually, the answer has to be C.
You must multiply 0.063 by (3!/2!), which equals 3, to get 0.189.
So, the equation will be : (0.3)^2 * 7 * (3!/2!)
These are the three ways in which the favorable event can take place (B=Buy, N=Not Buy)
BBN = 0.063 (First & Second person buys | third doesn't buy)
BNB = 0.063 (First & Third person buys | second doesn't buy)
NBB = 0.063 (Second & Third person buys | first doesn't buy)
Total = 0.189
