In the summer camp, there are 50 children. One sixth of the girls and one eighth of the boys cannot swim. 43 children can swim. How many girls are in the camp?
Let the number of girls in the camp be $x$, then the number of boys is $50-x$. From the problem statement, we have that

$$
\frac{x}{6}+\frac{50-x}{8}=7 .
$$

The solution to this equation is $x=18$.

There are 18 girls in the camp.

[2 points for setting up the equation, 6 points for the complete solution]