Answer: There are 18 students in a van and 24 students in a bus.
Explanation:
Let the number of students in the van be 'x' and the number of students in bus be 'y'.
Then, According to the question, we have the following system
![\text{[High School A ]}\ x+10y=258........................(1)\\\\\text{[High School B ]}\ 8x+5y=264........................................(2)\\](https://img.qammunity.org/2020/formulas/mathematics/middle-school/244zogacwnk46wixrrbyh3mduexhj28g99.png)
Multiply 2 to both the sides of equation (2), we get

Subtract equation (1) from equation (3), we get

Substitute value of x in (1), we get

Hence, there are 18 students in a van and 24 students in a bus.