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# How many books did the author write?

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Re: How many books did the author write? [#permalink]
We need to find number of books, which would be best sellers+non-best sellers.
A. Of the books the author wrote, 3 were bestsellers. - Doesn't give us total no. of books but only best sellers.
B.Of the books the author wrote, 80 percent were not best-sellers. - Gives us percent of non best sellers but not number.

If we combine A and B,
from B, Best sellers = Total - non best sellers
Best sellers = 100-80 = 20%

from A, Best sellers = 3
Lets suppose Total be variable X.

So, 20% of X is 3
so X is 15.
Both statements are required to answer the questions, Hence C.
Re: How many books did the author write? [#permalink]
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