6.3. In each of the three chests, Ali-Baba found gold and silver coins; in total, there were 40 gold and 40 silver coins. In the first chest, there were 7 more gold coins than silver coins, in the second chest, there were 15 fewer silver coins than gold coins. Which type of coin is more in the third chest and by how many? Explain your answer.
Answer: There are 22 more silver coins.

Solution. In the first two chests, the total number of gold coins is $7+15=22$ more than the total number of silver coins. Since initially there were an equal number of gold and silver coins, there are 22 fewer gold coins than silver coins in the third chest.

## Evaluation criteria:

+ complete and justified solution

$\pm$ correct line of reasoning, but an arithmetic error was made in addition

$\pm$ the correct answer and the operation $7+15=22$ are provided

干 the correct answer is obtained based on the specific values of the number of coins in the chests

干 only the correct answer is provided

- the task is not solved or is solved incorrectly