Explanation for Question 14 From the Math (Calc) Section on the Official Sat Practice Test 6
Question 14 asks us the growth rate of the sunflower from day 14. 2 Today 35 is nearly constant on this interval, 3 which of the following equations, best models, the height H and centimeters of the 4 sunflower T days after it begins to grow. 5 So I boxed in this interval is really important. 6 So we're really only looking at day 14 today, 7 35. So let's go and find that on the graph. 8 All right. So 14 to 35 is right here and I've highlighted your first 9 point and your last point. So essentially what we're trying 10 to do is we're trying to find an expression that effectively models lists. 11 The first thing that we can do pretty easily is find the slope of 12 this line. And we can do that by finding rise 13 over run. And we can use these two points that are pretty clear on 14 the graph. So our first point is going to be 1440, 15 as you can see from the left-most point right there. 16 So 1440 is right here, and then the next point is going to be 17 35 and then about, 18 let's say 1 35, noting that that's an approximation and that we might have 19 to round a little bit to get the answer choices. 20 So now we're going to do Y two minus Y one over X, 21 two minus or Y two minus Y one over X two minus X one. 22 So that'd be 1 35 minus 40, 23 over 35 minus 14. 24 So 1 35 minus 40 is going to be equal to 95. 25 Scott 95, over 35 minutes. 26 14 is going to be equal to 21. 27 So we have 95 over 21. And now let's simplify that down. 28 We have 4.52. 29 Okay. So our slope is equal to...