<span>The current is 6 miles per hour.
Let's create a few equations:
Traveling with the current:
(18 + c)*t = 16
Traveling against the current:
(18 - c)*t = 8
Let's multiply the 2nd equation by 2
(18 - c)*t*2 = 16
Now subtract the 1st equation from the equation we just doubled.
(18 - c)*t*2 = 16
(18 + c)*t = 16
(18 - c)*t*2 - (18 + c)*t = 0
Divide both sides by t
(18 - c)*2 - (18 + c) = 0
Now solve for c
(18 - c)*2 - (18 + c) = 0
36 - 2c - 18 - c = 0
36 - 2c - 18 - c = 0
18 - 3c = 0
18 = 3c
6 = c
So the current is 6 mph.
Let's verify that.
(18 + 6)*t = 16
24*t = 16
t = 16/24 = 2/3
(18 - 6)*t = 8
12*t = 8
t = 8/12 = 2/3
And it's verified.</span>
This method is known as linear perspective.
When using linear perspective, artists use a set of drawn or imaginary lines which are made to converge at the horizon of the image. These lines change the viewer's perspective by providing a point through which the relative size, shape and position of objects is determined. This technique creates the illusion of depth.
If they are both traveling with the same speed that means that they will reach other in the middle of the line initially between them. In other word, each will have to travel the same amount before they reach other.
Now you can calculate the time it takes for only one locomotive to travel half of the total distance between them, and that time is equal to the time you are looking for.
Use
t = S1/2 / v
where t-time, S-distance traveled , v-velocity
Sound waves need a medium to go through and are created through vibrations, whereas light waves need no medium, meaning it can move through space. Light also doesn’t loose energy when reflected, but sound waves get absorbed by the medium they go through causing it to loose energy.
