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Mary wanted to buy 3 books worth Php450. If Mary wanted to buy 5 books, How much will the books cost? If mary have Php800 of buying the books and Php50 of going back home, will she have enough money?

What is asked-How much will the books cost? 
Given-Php450, 5 books,3 books
          Php150 whorth of 1 book. Now,

Final answer- Php750 the books will cost.
                       Yes. But there will be no left money because she already spent the remaining Php50 of her 800 and subtracting the books, that cost Php750.