925. What is the smallest number of members in a math club if the number of girls in it is more than $40 \%$, but less than $50 \%$?
Let in the club there be $a$ girls, and the total number of club members is $b$. Then the ratio of the number of girls to the total number of club members is $\frac{a}{b}$.

Since $40 \%$ is $\frac{2}{5}$, and $50 \% - \frac{1}{2}$ of the club members, then by the condition

$$
\frac{2}{5}<\frac{a}{b}<\frac{1}{2}
$$

We need to find the smallest natural number $b$, for which there exists such a natural number $a$, for which the written inequality is true.

This is a problem of the same type as problem 922. Therefore, the further solution is carried out in the same way. Complete it independently.

Answer: 7.