Question 6
Peter starts with some 100-ruble notes and no other money. Books have positive integer prices. Change is in 1-ruble coins. For an expensive book (price at least 100), he pays with the fewest 100-ruble notes needed. For a cheap book (price below 100), he pays with coins if he has enough, otherwise with one 100-ruble note. When all notes are gone, he has spent exactly half his initial money. Could he have spent at least 5000 rubles? (The official English original uses dollars; the supplied Vietnamese uses rubles. The arithmetic is unchanged.)
