Let's say that the speed of the freight train is and the one of the passenger train is
.
MPH means every hour the freight train covers
miles., which means in 3h it will have covered 3 times as much:
mi.
Following the same logic, MPH means every hour the passenger train covers
miles, meaning after 3h it will have covered 3 times as much as well:
mi.
Now, having expressed those distances and speeds algebraically, we find the difference between the two distances covered after 3h, knowing it will be equal to 240:
Knowing this, we can surely affirm that the freight train is travelling at 40MPH and the passenger train is travelling three times as fast, 120MPH.
Answer:
8 (7.94)
Step-by-step explanation:
You can think of it as a geometry problem.
What is formed here is a triangle, which sides ate: the line, the line's shadow, and the height from the ground to the kite (here I attach a drawing).
What you need to find is the height. We will call it H.
As the triangle formed is a right one, we can use Pitágoras' theorem. The height H squared plus the squared of the shadow is equal to the squared of the line (the hypotenuse). This is:
H^2 + 9^2 = 12^2
H^2 + 81= 144
H^2 = 63
Applying squared root in both sides
H = √63
H = 7,94
So, the height is approximately 8.
