a typo on topscore?

[Smooth Operater]

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A woman carries a sex-linked lethal gene that causes spontaneous abortions. She has six children. How many of her children would you expect to be boys?

The answer is TWO children will be boy, but the answer mentions the woman has EIGHT children in total.

Am I wrong?

 

[Ms.Dentista]

I am not sure of the exact question, but I do know that topscore def has some typos in it. There is a section on the scholarware website that gives updates on the typos that have been found in the practice tests. You might want to check and see if that question was posted. 🙂

 

[Streetwolf]

Negative, no typo.

Woman is XX(c) where X(c) denotes mutation and X is wild-type.
Man is XY (normal).

Possible children are:

XX
X(c)X
XY
X(c)Y

Of which 3 live and 1 dies (X(c)Y). Multiply by 2 and you get 6 live and 2 die. Of the 6 children, 2 are boys.

So you expect 2 boys, 4 girls, and 2 aborted boys = 8 total. But the question asks for living boys so the answer is 2.