Answer:
4.5 hours
Step-by-step explanation:
To answer this, we shall be using a diagrammatic representation.
Now, let the time taken for them to be 54 miles apart be x hours
Mathematically, distance = speed * time
For the north bound boat, it would be 4 * x miles away = 4x miles away from the starting point
For the south bound boat, it would have travelled a distance of 8 * x = 8x miles
Now the distance between both is 54 miles ; this means that by adding the distance traveled by both, we shall have a total length of 54 ;
Thus mathematically;
4x + 8x = 54
12x = 54
x = 54/12 = 4.5 hours
