7.13. In the report on the ski race, it is stated that $96 \%$ of its participants met the standard. It is known that this figure is given with an accuracy of $0.5 \%$. What is the smallest number of participants in this race?
7.13. Let $n$ be the number of skiers in the race, and $k$ be the number of them who did not meet the standard. According to the condition, $3.5 \leqslant 100 k / n \leqslant 4.5$. Therefore, $k \geqslant 1$ and $n \geqslant \frac{100 k}{4.5}>22.2 k \geqslant 22.2$. Hence, $n \geqslant 23$. If there were 23 skiers in the race, and only one did not meet the standard, then the required condition is satisfied.