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In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world. 
 Answer: 10,000,000 or less.
Solution: How many books are there in the British Library?
Why? In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

New input: Article: Children who grow up in households where books are plentiful go further in school than those without books, a new study finds. This book benefit was seen across countries, and held regardless of the parent's educational back-ground, father's occupation or the political system of the country, the researchers say. The results, based on data from 73,249 people living in 27 countries, including the United States, show that having a 500-book library boosted a child's education by 3.2 years on average. "You get a great effect for your books," said study researcher Mariah Evans, a sociologist at the University of Nevada, Reno. "It's quite a good return-on-investment in a time of scarce resources." For years, educators have thought the strongest predictor of attaining high levels of education was having parents who were highly educated. But according to the findings, a good-sized book library is just as good as university-educated parents in terms of increasing education level. "Even a little bit goes a long way," in terms of the number of books in a home, Evans said. Having as few as 20 books in the home still has a significant impact on propelling a child to a higher level of education, and the more books are added, the greater the benefit. In some countries, such as China, having 500 or more books in the home propels children 6. 6 years further in their education. In the United States, the effect is less, 2.4 years. But, Evans points out that 2.4 years is still a significant advantage in terms of educational achievement. For example, Americans who have some college or an associate's degree, but not a bachelor's degree, earn an average of $ 7,213 more annually than those with just a high school education. Those who attain a bachelor's degree earn $ 21,185 more each year, on average, than those with just high school diplomas. Having books in the home is twice as important as the father's education level, and more important than whether a child was educated in China or the United States. 
 Answer: To show the importance of books in the home.
Solution:
What was the author's purpose of writing the passage?