ANSWER
A maximum of 38 students can attend the trip. (Option C).
Step-by-step explanation
Given:
Number of students function: N = x + y
$150x + $120y < $4,800 ................equ 1
15x + 20y < 720.................................equ 2
where
x = Students traveling by train
y = Students traveling by bus
Multiply equation 2 by -10
Add equation 1 and 3
150x + 120y < 4,800
-150x - 200y <-7200
-----------------------------
0x - 80y < -2400
y > 2400/80
y > 30
Substitute the value of y into equation 1 to solve for x
150x + 120y < 4,800
150x + 120(30) < 4800
150x < 4800 - 3600
x < 1200/150
x < 8
Number