[Video] Q35: The line graph shows the total length, in miles, of major commercial railroad tracks in the united states from 1916 to 1976. the average rat e of change, in miles per year, of the total length of major commercial railroad tracks in the united states from 1916 to 1926 is m. what is the value of m?

Explanation for Question 35 From the Math (Calc) Section on the 2020 October Sat

So question number 35 is asking us what is the value of em? 2 And they tell us that M is true, 3 the average rate of change in miles per year. 4 And so one thing that's useful to note is that the rate of change 5 simply means the slope. So here, 6 right? Cause slope shows rise over run. It's showing change over time. 7 And so the rate of change, we can look at the slope. So all 8 that means is that we want to find the slope between the point at 9 1916 and 1926. 10 And so it's really easy. We can just do is rise over run. 11 And so our rise, we rent, we went from four 21,000 12 minus three, nine, 7,000. 13 That was our change in our Y value. And then our change in our 14 X value is 1926 minus 1916. 15 And so this will give us 24,000 and this will give us 10. 16 So now we can simplify this. These zeros will cancel. 17 We get 2,400 over one or a simple value of M 18 of 2,400, just by finding the slope and doing rise over, 19 run like a normal line equation.