Answer:
20 students for $160
Explanation:
bus a: y = 6x + 40
bus b: = 2x + 140
x = # of students | y = cost
FOR X: *set equations = to each other*
6x + 40 = 2x + 140 *subtract 2x from both sides*
4x + 40 = 120 *subtract 40 from both sides*
4x = 80 *divide by 4 on both sides*
x = 20
FOR Y:
y = 6x + 40 *plug in 20 for x and solve*
y = 6 (20) + 40
y = 120 + 40
y = 160