Answer:
120 miles in 4.8 hours
75 miles in 5 hours
Step-by-step explanation:
Ship:
The number f(x) of miles a ship is from its destination x hours after starting a voyage is given by f(x) = 120 - 25x. This means, initially the ship is 120 miles away from its destination.
If the ship traveled 120 miles, then f(x)=0 (the ship will be 0 miles away from its destination) and
0 = 120 - 25x
25x = 120
x = 4.8 hours.
Submarine:
At x = 0 hours the submarine was 75 miles away
At x = 5 hours, the submarine was 0 miles away.
So, in 5 hours the submarine traveled 75 miles
