18. (3 points) When Xiaoming goes from home to school, he walks the first half of the distance and takes a ride for the second half; when he returns from school to home, he rides for the first $\frac{1}{3}$ of the time and walks for the last $\frac{2}{3}$ of the time. As a result, the time it takes to go to school is 2 hours more than the time it takes to return home. It is known that Xiaoming walks at a speed of 5 kilometers per hour and rides at a speed of 15 kilometers per hour. Therefore, the distance from Xiaoming's home to school is $\qquad$ kilometers.
18. (3 points) Xiaoming walks the first half of the journey from home to school and takes a ride for the second half; when he returns from school to home, he rides for the first $\frac{1}{3}$ of the time and walks for the last $\frac{2}{3}$ of the time. As a result, the time it takes to go to school is 2 hours more than the time it takes to return home. It is known that Xiaoming walks at a speed of 5 kilometers per hour and rides at a speed of 15 kilometers per hour. Therefore, the distance from Xiaoming's home to school is $\qquad$ kilometers.

【Solution】Solution: The time it takes to go from home to school is:
$$
\begin{array}{l}
\frac{1}{2} \div 5+\frac{1}{2} \div 15 \\
=\frac{1}{10}+\frac{1}{30}, \\
=\frac{2}{15} ;
\end{array}
$$

The time it takes to go from school to home is:
$$
\begin{array}{l}
1 \div\left(5 \times \frac{2}{3}+15 \times \frac{1}{3}\right) \\
=1 \div 8 \frac{1}{3} \\
=\frac{3}{25}
\end{array}
$$

The distance between home and school is:
$$
\begin{array}{l}
2 \div\left(\frac{2}{15}-\frac{3}{25}\right) \\
=2 \div \frac{1}{75}, \\
=150 \text { (kilometers); }
\end{array}
$$

Answer: The distance from Xiaoming's home to school is 150 kilometers.
Therefore, the answer is: 150 .