Answer:
1.2 hours
Explanation:
Recall :
Distance = speed * time
Let the time taken = x
Creating an equation for the question :
Distance of train A + Distance of train B = 192
70 * x + 90 * x = 192
70x + 90x = 192
160x = 192
x = 192 / 160
x = 1.2
It takes 1.2 hours to be 192 miles apart.