You will be given a definition of a task first, then an example. Follow the example to solve a new instance of the task.
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: The struggle to "have it all" leaves many mothers giving up their health and hobbies. But dads have more time to spare according to a research, with just 55 per cent saying they lose sleep and regular exercise compared with 71 percent of mums. Twice as many mothers as fathers complained that they did not spend enough time relaxing, with almost half of mums spending less than two hours a week with friends. And more than a third miss out on hobbies and interests because they are too busy. In spite of changing roles in the family, women are still responsible for most of the child care. Nearly a third spend more than 10 hours a week caring for their children, compared with just one in ten fathers. More mums than dads also say housework and tiredness stop them achieving their goals. But the research also shows mums gain a sense of achievement from finishing the housework, getting their children to school on time or sitting down to a family dinner. The research underlines the fact that women feel under pressure to succeed in all areas of their lives. As Nick Booth, a marketing director put, "They are pushing themselves too hard and are in danger of burning out. We'd encourage anyone to take time out for themselves. Having your own interests and hobbies and ensuring you get enough sleep is hugely important. Other parts of your life, including work and family life, improve as a result."  The Olympian  and mother Jo Pavey admitted balancing career, family and personal time can be a struggle. Jo, 41, became the oldest female gold medalist at the European Championship last year - but regards her children as her biggest achievement. The mum of two said,"When I was younger,I'd have probably said it wasn't possible to have a sporting career and be mum. But actually it is all about striking a balance and looking after yourself." 
 Answer: Being tired with much housework.
Solution:
Which of the following prevents mums from achieving their goals?