Explanation for Question 7 From the Math (No Calc) Section on the 2020 October Sat
So question number seven, this is a nice lengthy word problem. 2 And whenever we have one of these in the math section is always useful 3 to underline whatever information you think is most important. 4 And so here what's really important is that we have 75 square miles on 5 a robot in 19 square miles on Bermuda. 6 And then we also have this equation that we've written, 7 um, which estimates the number of residents T on the two islands. 8 And we're trying to figure out what X is. 9 And really this is a question about units, right? 10 Cause we're trying to figure out if X means residents, 11 if X is miles, what is the unit on X? 12 And so if you want to look up more information on how to do 13 this, these are pretty, fairly common questions. 14 This is called unit analysis. And we can see from our equation, 15 if we plug in all the units that we know we have 75 square 16 miles. 17 So I put a mile squared on the 75 and it was the same 18 for the 19. And then the question also told us that T represented the 19 number of residents. So residents. 20 And so the bottom line is that whatever this value is and whatever this 21 value is, when I add the units on those, 22 they have to be in the units of residents because 23 I'm equaling it to residents, right? 24 So if you have two dogs, plus two dogs, 25 you get two dogs, right? Whatever units you have here, 26 and here has to be the same of what you get in the end. 27 You can't change units when you add things together. 28 And so for ...