To figure out this equation, let's break it down
there were 217 students
5 buses
7 students left over
first we need to take away the 7 students from the 217 students total so we are left with an even number.
217 - 7 = 210
and since there were 5 buses filled with students we divide by 5 (assuming they all hold the same capacity)
210 ÷ 5 = 42
Answer: there were 42 students in each bus
Hope this helped! :D