6.4. Three pirates were dividing a bag of coins. The first took 3/7 of all the coins; the second took 51 percent of the remainder. After this, the third received 8 fewer coins than the second. How many coins were in the bag? Justify your answer.
Solution: The third pirate received $49\%$ of the remainder, which is $2\%$ less than the third. These two percent of the remainder amount to 8 coins, so one percent is

4 coins, and the entire remainder is 400 coins. These 400 coins make up $1-\frac{3}{7}=\frac{4}{7}$ of the total. Therefore, the total number of coins in the bag was $400: \frac{4}{7}=700$.

Answer: 700 coins.

Recommendations for checking:

| is in the work | points |
| :--- | :--- |
| Correct and justified answer | 7 points |
| Answer is incorrect only due to arithmetic errors | 6 points |
| Correctly and justifiedly found the number of coins received by one or two pirates | 4 points |
| Correctly formulated, but not solved (or solved incorrectly) equation (or system of equations) that fully describes the problem | 3 points |
| There is an idea (not brought to a solution) to solve the problem from the "end" | 2 points |
| Correct answer without justification | 1 point |
| Principally incorrect reasoning | 0 points |