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.
For all of them you can just simplify to their lowest fractions like this and they'll still be equivalent 2/10, 1/4, 9/10
Well what you would have to do is look for numbers that are easy to divide. For example, lets try 9000/10, and so the answer would be 900 and so if you divide the actually numbers, you could compare them, and see if 900 would be a reasonable.
We can create two points.
30 feet below the surface of the water 10 seconds after he entered the water
100 feet below the surface after 40 seconds
So we have (10, 30) and (40, 100)
Plug this values into the slope formula:
m = y2-y1/x2-x1
m = (100 - 30)/(40 - 10)
m = 70/30
m = 2 1/3
I got S > 2
Because you would multiply both sides by two then subtract by twelve
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