Answer:
2 miles
Step-by-step explanation:
Their combined speed (speed of closure) is 80 mph + 40 mph = 120 mph.
120 mi/h = 120 mi/(60 min) = 2 mi/min
The distance between the trains at the 1-minute mark is ...
(1 min) · (2 mi/min) = 2 mi
They were warned when two miles apart.
Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
or 
In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin
Let
m ----> the distance in miles (y-coordinate)
h ----> the time in hours (x-coordinate)
In this problem the constant of proportionality k is given and is equal to
----> the speed
substitute

They already spent $2000, and they only had $5100
Subtract
5100 - 2000 = 3100
$3,050 is your answer, because it is the only one that is less than 3100
hope this helps