Explanation for Question 34 From the Math (Calc) Section on the 2020 March Sat
So here in question number 34, we're given information about popcorn and pretzels. 2 And for the pretzels, they tell us that we have 120 calories, 3 12 of which are from fat. And for the popcorn, 4 we have 150 calories 90 of which are from fat. 5 And then they ask us how many more calories from fat are provided by 6 a 100 calorie serving of microwave popcorn. 7 Then by a 100 calorie serving of pretzels. 8 So what we can see here is that we need to be talking in 9 terms of 100 calories, not 150 and 112. 10 So that shows us that we need to convert from 150 calories to 100 11 calories. And that's going to allow us to use proportions, 12 right? Because we're trying to change the numbers without changing the units. 13 So I'll start by doing my proportion with the popcorn. 14 They tell us, they told us that 150 calories is 90 calories from 15 fat, which I'll abbreviate as CF. 16 So I'm going to write my fraction that shows that ratio, 17 right? But remember, I'm not interested in 150 calories. 18 I'm interested in 100 calories. So since I put the one 50 on the 19 numerator of my left-hand fraction, I'm going to put what I'm actually interested on 20 the numerator of my right hand fraction, which was the 100 calories. 21 What's really important is that you have count. If, 22 if you have calories in the numerator of one, you need calories in the 23 numerator of your other fraction. And again, 24 I don't know how many calories from fat or in a hundred calories, 25 that's what I'm goin...