Task 1. In a confectionery store, three types of candies are sold: caramels for 3 rubles, toffees for 5 rubles, and chocolates for 10 rubles. Varya wanted to buy exactly 8 candies of each type and took 200 rubles with her. In the morning, she saw announcements in the store: “When paying for three chocolates, get a free toffee at the cash register.” and “When paying for three toffees, get a free caramel at the cash register.” How much money will Varya have left?
Answer: 72 rubles.

Solution. Since Varya will buy more than six but less than nine chocolates, she will get two free caramels. Then she will need to buy another 6 caramels, for which she will get two free toffees, after which she will need to buy another 6 toffees. Then she will spend a total of $8 \cdot 10 + 6 \cdot 5 + 6 \cdot 3 = 128$ rubles. In this case, she will have $200 - 128 = 72$ rubles left.