# Determine the cost of the book [closed]

Two sisters, Saraha and Jane, go to a book store to buy an algebra book. Saraha is 10 dollars short for the book, and Jane is 1 dollar short. However, if the sisters combine their money, they still don't have enough for the book!

If neither of the sisters have any change in their pocket (Any coin or note lower than a dollar), what is the price of the book?

• Because 8 of the 11 countries that use a currency named "Dollar" have a $1 coin instead of a bank note, the answer to this puzzle is ambiguous. – Ian MacDonald Apr 20 '16 at 17:53 • @IanMacDonald It's only ambiguous if that dollar has a fractional note. From Wikipedia, there are a handful of dollars for which the smallest banknotes are 2 and 5, in which case the expected answer still holds. For countries whose bank notes start at 5 or higher, then the reasonable answer is: "This puzzle doesn't occur in that country, but in another one." And, after all that, the Bahamian dollar does offer half-dollar notes (though Wikipedia says they are rarely used), in which case the book could cost BSD9.50 or BSD10. – Matt Apr 20 '16 at 18:35 • @Matt, not true. Since the currency is not precisely defined, and the vast majority of "dollar" currencies have no$1 note, the majority answer is "there is no solution". It is only in the minority of cases that there could potentially be a solution. This is what makes answering ambiguous: there is more than one possible answer given the information in the puzzle. – Ian MacDonald Apr 20 '16 at 18:44