According to the question statement, the total sum of students is 221, which includes the students that ride on bus and the students that ride in a van.
The students that ride in a van are five, the students that ride on bus are 6 times s which is the product of the number of buses and the number of students that are on each bus.
Write all this information into an equation, this way:
Now, solve the equation for s to find the number of students that are on each bus.
There are 36 students on each bus.