Answer:
-2
Step-by-step explanation:
add the -5 and -11, then add on to it the 14
44. 76 grams. you just have to add up the weights!
Let's look at the picture, let's imagine that the gray line is the perimeter fence and that the red OR the blue is the one dividing it. We can see that the blue line is longer than the red one, so it will be advantageous, to have a bigger area, to have the dividing fence the smallest possible.
Let's say then that the width (W) is bigger (or equal) to the length (L), so we have:

The area is W*L, so we have

this function is a parabola facing down, its zeros are 0 and 80, therefore its maximum is when L=40
hence, L=40 and W=(240-120)/2=60
It will be a rectangle, measuring 60x40 and the divinding fence will be 40
Imagine you're on the first train. since you're moving away from second train at 70mph, and that train is moving away from you at 80mph, in total that other train for you is moving away at 150mph (as you are stationary inside the train).
if the two trains are moving apart at 150mph, then to be 600 miles apart it will take 600/150 hours, which you can calculate :)