Answer:
1 bus = 15 students, 1 van = 54 students
Explanation:
A: 3v + 12b = 693
B: 2v + 2b = 138
Add 555 to both sides of equation B to make the sums equal.
2v + 2b + 555 = 693
This can also be seen as:
2v + 2b + 555 = 3v + 12b
Subtract 2v from both sides.
2b + 555 = v + 12b
Subtract 2b from both sides.
555 = v + 10b
With some guess and check, and substituting:
1 bus = 15 students, 1 van = 54 students