Answer:
3x + 4.5x + 1 = 28
3.6 seconds
Explanation:
Initial distance apart = 1 foot
Student A:
Walk rate = 3 ft per second
Student B:
1.5*3 = 4.5 ft per second
How long it will take to be a total of 28 feets apart
Distance = speed * time
Let time = x in seconds
Student A distance = 3x
Stident B distance = 4.5x
Initial distance = 1 foot
3x + 4.5x + 1 = 28
7.5x = 28 - 1
7.5x = 27
x = 27/ 7.5
x = 3.6 seconds