# Task 8.2 (7 points)

The shares of the company "Nu-i-Nu" increase in price by 10 percent every day. Businessman Borya bought shares of the company for 1000 rubles every day for three days in a row, and on the fourth day, he sold them all. How much money did he make from this operation?
Solution: $1000 \cdot 1.1^{3}+1000 \cdot 1.1^{2}+1000 \cdot 1.1-3 \cdot 1000=1331+1210+1100-3000=641$.

| Criteria | Points |
| :--- | :---: |
| Complete solution | 7 |
| Correct approach with arithmetic error | 4 |
| Correct answer without justification | 0 |

## Answer: 641 rubles

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