7. (10 points) A toy store sells a type of building blocks: each starship costs 8 yuan, and each mech costs 26 yuan; one starship and one mech can be combined to form an ultimate mech, which is sold for 33 yuan per set. If the store owner sold a total of 31 starships and mechs in a week, and the total revenue was 370 yuan; then how many starships were sold individually?
【Solution】Solution: Let the number of starships sold individually be $x$, the number of mechs sold individually be $y$, and the number of bundle sales be $\frac{31-x-y}{2}$
$$
8 x+26 y+\frac{31-\mathrm{x}-\mathrm{y}}{2} \times 33=370
$$

Simplifying, we get: $17 x-19 y=283$
Since $x$ and $y$ are integers less than 31, and $17 x$ is greater than 283, then $x>16$. Using enumeration, we can solve for $x=20, y=3$.

Therefore, the answer is: 20