Question

The number f of miles a ship is from its destination x hours after starting a voyage is given by f (x) = 120 - 25x. The number f of miles a submarine is from its destination x hours after leaving port is shown in the graph below

state the distance and length of time of each voyage.

The ship traveled 120 miles in ___ hours. The submarine traveled ___ miles in 5 hours.​

Answer 1

The ship traveled 120 miles in 4.8 hours.

The submarine traveled 75 miles in 5 hours.​

Explanation:

In this case, we just have to use the given graph to answer correctly the submarine voyage. In addition, the given function relates Hours with Distance (miles) about a ship voyage. First, the problem is asking about the time when it traveled 120 miles, and it's asking the distance after traveling 5 hours, to answer that question we just have to see what values belong to each question.

So, the expression
`f(x) = 120 - 25x` specify that the ship is starting from 120 miles away the objective, because when x = 0 (the initial point), y = f(x) = 120. This means that after traveling 120 miles, the ship will be 0 miles away, so f(x) = 0. Replacing this value we will find the needed time to travel 120 miles.

`f(x) = 120 - 25x`

`0= 120 - 25x`

`25x= 120`

`x=(120)/(25)=4.8`

Therefore, it will require 4.8 hours to travel 120 miles.

The second question is asking miles traveled after 5 hours by the submarine. In this case, the graph belongs to the submarine. We observe that in x = 5 hours, the distance traveled is 75 miles, because the line dropped from 75 to 0 miles, when went horizontally from 0 to 5 hours, meaning that after 5 hours, it traveled 75 miles.

Answer 2

120 miles in 4.8 hours

75 miles in 5 hours

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