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Alex had $76.  He spent some of it in a shop.  Then he gave half of what he had left to Charlie.  Charlie spent a quarter of what Alex gave him on lunch.  Charlie spent $9 on lunch.  How much did Alex spend in the shop? 
Overseas Competition->Knowledge Point->Word Problem Modules
Charlie\textquotesingle s 1/4 is 9, so Charlie gets 4\times 9=36 dollars, and Alex is left with 36+36=72 dollars, so he spends 76-72=4 dollars 