In High school A 3 filled vans: 51 students and 102 students in buses, In High School B, 153 students in vans and 480 in buses.
1) Given the data:
High School A
3 vans + 6 buses, 291 students
High School B
9 vans, 12 buses and 633 students
2) We can write the following system of equation:
3v +6b = 291
9v +12b=633
Let's use the Elimination/Addition Method to solve that equation
3v +6b = 291 x (-2)
9v +12b=633
Add both equations simultaneoulsy:
-6v -12b = -582
9v +12b=633
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3v =51
v=17
Plugging that value into the simplest equation
3(17) +6b = 291
51 +6b=291 Subtract 51 from both sides
6b=240
b=40
2) So there were 40 buses and 17 vans. In High school A 3 filled vans: 51 students and 102 students, In High School B, 153 students in vans and 480 in buses.