Explanation for Question 12 From the Math (Calc) Section on the 2019 April Sat
For number 12, we are looking at this information here and we want to 2 know what the number seven represents in the equation. 3 So here is the equation, 4 but the part that we are mostly focused on is this part, 5 since that's the only part that involves the seven. 6 So since it says Shayla ran for 17 miles, 7 that means we can get rid of any answers that involve walking. 8 Since that's talking about a different part of the equation, 9 so we can get rid of a and C. 10 So now, if we know that she ran seven 11 T miles, that means that seven times T is going to give us 12 a distance of however many miles. 13 The important part is we're looking for units of distance. 14 We know that T is a measure of time, 15 so you need to multiply something by the time in order to get distance. 16 And if you know, speed times time gives 17 you distance. 18 That would help you answer this question a lot quicker. 19 So B is the correct answer. 20 You can also do a bit of dimensional analysis if you forget the formula 21 for distance. So we know T is in hours. 22 So here is our hours and we're looking for our units 23 of seven. So I'm going to leave this part blank right here, 24 and it should equal a distance in miles. 25 So we need to have a mile somewhere. 26 So I would put miles here and there are no hours in our final 27 answer. So that means we have to get rid of it somehow. 28 And since we are multiplying it, we would have to divide out the hour. 29 So now we have miles per hour, 30 times hours will give us miles. And if we cancel that out, 31 it checks out. So now if you know, 32 miles per hour here, that is, 33 that is a unit of speed. 34 So B is the correct answer.