9514 1404 393
Answer:
B, D
Step-by-step explanation:
The cubic function is plotted in the attachment. It is a curve found in quadrants I and III, so is not symmetric about the y-axis.
Its domain and range are all real numbers, and it passes through the origin.
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.