Explanation for Question 10 From the Math (No Calc) Section on the 2019 October Sat
Now for number 10, we're given this equation here, 2 which says that a is equal to 1,321 plus 3 0.3443 M. 4 And the question tells us that this equation estimates the body surface area, 5 which is a, so this is body surface area and square centimeters 6 of a child with mass M. So M is the mass of the child. 7 Um, and we're N has to be between 3000 and 30,000. 8 And so now it's asking us which of the following statements is consistent with 9 the equation. And so the first thing that I want to point out is 10 this is really the equation of a line, 11 right? We have a line here and we know that it's aligned first off 12 because it has a slope, right? 13 Where M is actually like an X value. 14 Um, an a is actually like a Y value. 15 So I could rewrite the equation. As for example, 16 Y equals one, three to one, plus 0.3, 17 four, four X. 18 And now if I simply switched, um, the placement of these two, 19 we have the equation of a line. So what's important to note is that 20 our 1, 3, 2, 1 is our Y intercept. 21 And the 0.3, 3.3, 22 4 43 is actually the slope. So now let's look at answer choice a, 23 which tells us that for each increase in one gram of mass. 24 So each time I increase M by one, 25 essentially, um, EI increases by 0.3, 26 4, 3, 3 square centimeter. 27 And that should make sense, right? Because say that I have an AMH of 28 one that means that I'm adding 0.3, 29 4, 4, 3 square centimeters. But if I had an M of two, 30 I would be doing 0.3, 4, 4, 3 times two. 31 So I'...