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If a family has three children, what is the probability that the famil

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If a family has three children, what is the probability that the famil  [#permalink]

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New post 25 May 2018, 03:24
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A
B
C
D
E

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  15% (low)

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77% (00:55) correct 23% (01:34) wrong based on 110 sessions

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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 25 May 2018, 04:03
Bunuel wrote:
If a family has three children, what is the probability that the family has at least one girl?


A. 1

B. 0.875

C. 0.75

D. 0.50

E. 0.375




The probability that all three children are boys is 0.5*0.5*0.5 = 0.125

The probability that the family has at least one girl is 1-0.125 = 0.875

Hence Option B = 0.875 is the answer.
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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 25 May 2018, 04:44
Probability of having at least one girl =1- Prob of all boys
Prob of having all boys =0.5*0.5*0.5
Answer =1-0.125=0.875 "B"
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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 26 May 2018, 06:01
Probability of having atleast a girl= 1- Probability of having all boys

Probability of having a boy= 1/2
Probability of having three boys= (1/2)(1/2)(1/2) = 1/8

Probability of having atleast a girl = 1- (1/8) = 7/8 = 0.875

Correct Answer= B
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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 29 May 2018, 08:16
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Bunuel wrote:
If a family has three children, what is the probability that the family has at least one girl?


A. 1

B. 0.875

C. 0.75

D. 0.50

E. 0.375


The two events “at least one girl” and “no girls” are complementary events, which means that the sum of their probabilities is 1. Thus, we have:

P(at least 1 girl) = 1 - P(no girls)

P(no girls) = 1/2 x 1/2 x 1/2 = ⅛

So, P(at least 1 girl) = 1 - P(no girls) = 1 - 1/8 = 7/8 = 0.875.

Answer: B
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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 29 May 2018, 12:24
Bunuel wrote:
If a family has three children, what is the probability that the family has at least one girl?


A. 1

B. 0.875

C. 0.75

D. 0.50

E. 0.375


Total sample space = BBB,BBG,BGB,GBB,GGB,GBG,BGG,GGG where G=Girl and B=BOY

probability that at least one of the children will be girl = 7/8 = .875
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Re: If a family has three children, what is the probability that the famil  [#permalink]

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New post 31 Jan 2019, 17:47
Bunuel wrote:
If a family has three children, what is the probability that the family has at least one girl?


A. 1

B. 0.875

C. 0.75

D. 0.50

E. 0.375


We can use the formula:

P(at least one girl) = 1 - P(no girls)

P(no girls) = (1/2)^3 = 1/8.

P(at least one girl) = 1 - 1/8 = 7/8 = 0.875.

Answer: B
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Re: If a family has three children, what is the probability that the famil   [#permalink] 31 Jan 2019, 17:47
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