Answer:
<h2>x = 1</h2>
Step-by-step explanation:
Look a t the picture.
The triangles on the picture are similar.
Therefore the sides are in proportion:
<em>cross multiply</em>

<em>divide both sides by 40</em>

Answer:
-1.66666666667 yards
Step-by-step explanation:
15x+12=6x-3
subtract 6x on both sides
9x+12=-3
subtract 12 on both sides
9x=-15
x=-1.6666666666667
"He starts both trains at the same time. Train A returns to its starting point every 12 seconds and Train B returns to its starting point every 9 seconds". Basically, what you need to do is find the least common multiple. The least common multiple of 12 and 9 is 36, so the least amount of time, in seconds, that both trains will arrive at the starting points at the same time is 36 seconds.
54 square inches
Basically you just multiply