Explanation for Question 2 From the Math (Calc) Section on the 2019 October Sat
Now for number two, we're told that the distance between two locations on a 2 map is six centimeters. If one centimeter corresponds to an actual distance 3 of 15 miles. So one centimeter is actually 4 15 miles. What is the actual distance between the two locations? 5 And so this is going to be a proportions question. The reason being, 6 because first they give us a rate of conversion, 7 right? We know that one centimeter is 15 miles, 8 and then they give us one unit, right? 9 They give us the centimeters and we're asked to change that into miles. 10 So we'll start by writing. Our conversion factor is a fraction, 11 right? We have one centimeter is equal to 15 miles, 12 and I'm going to set that equal to another fraction, 13 where again, I'll put centimeters on the top and miles on the bottom, 14 because whatever you have on the top should be consistent and whatever you have, 15 whatever unit you have on the bottom should also be consistent. 16 Now we know that the distance between the two points is six centimeters. 17 So I'll put a six in my numerator, and then we know that we 18 are solving for the miles, right? So we actually don't know what the miles 19 are, so we can put a variable there and now I just simply have 20 to solve for X, right? So I multiply across one times X, 21 which is X. And then I multiply across here six times 15. 22 And so since this is the calculator section, 23 we can just plug that in and get 90, 24 right? So it tells us the X is equal to 90, 25 which means that our answer has to be C for 90 miles.