How much time is needed to write down the numbers ranging from 1 to 117639, if we write down 93 digits per minute?
Determine the number of digits to be written:

| $1-$ | 9 - | the number of digits | $9 \cdot 1$ | $=$ | 9 |  |
| ---: | ---: | ---: | :--- | ---: | :--- | ---: |
| $10-$ | 99 - | the number of digits | $90 \cdot 2$ | $=$ | 180 |  |
| $100-$ | 999 - | the number of digits | $900 \cdot 3$ | $=$ | 2700 |  |
| $1000-$ | 9999 - | the number of digits | $9000 \cdot 4$ | $=$ | 36000 |  |
| $10000-$ | 99999 - | the number of digits | $90000 \cdot 5$ | $=$ | 450000 |  |
| $100000-$ | 117639 - | the number of digits | $17640 \cdot 6$ | $=$ | 105840 |  |
|  |  |  |  | Total |  | 594729. |

The time required to write these digits according to the task is $\frac{594729}{93}$ minutes $\approx 6394 \mathrm{m} 56 \mathrm{s}=106$ hours $34 \mathrm{m} 56 \mathrm{s}=$ 4 days 10 hours 34 minutes $56 \mathrm{s}$

Katalin Eördögh (Bp., XIV., Blanka Teleki School I. o. t.)