Explanation for Question 24 From the Math (Calc) Section on the Official Sat Practice Test 10
Not for number 24, we're looking at a scatterplot here and we're trying to 2 decide which line best fits the scatter plots. 3 The line of best fit, right? That's this bold line right here. 4 So we can see here that all of our answer choices they're written in 5 a Y intercept form, Y equals MX plus B, 6 except they, none of them have a B, right? 7 We see there's no plus number. There's only the slope in the X. 8 So we're not worried about the B what we're really going to be focusing 9 on here is the slope. I noticed that the line of best fit here 10 goes up into the right, and that indicates a positive slope so 11 we can eliminate any we can eliminate see because our slope needs to be 12 positive. And now we can simply test B and 13 D to see which answer choice is going to be better with regards to 14 what number the slope should be. 15 And an easy way to do that is to pick a point and see 16 which one is true, which equation holds true when you plug in that point. 17 Right? And so this point is going to be one 40 comments, 18 70, right? And so if I plug it here in the answer, 19 choice B my Y is 70, and that's equal to 0.5 times one 40, 20 right? And half of one 40. 21 Sure. Enough is 70. So be as true, 22 70 is 70 B appears to work. 23 We'll just test it with the answer choice D to show you what an 24 incorrect answer would look like doing this. 25 Do you says that 70 is equal to two times R X, 26 which is one 40 and two times 140 is 280, 27 right? So somebody is not the same thing as 280. 28 They're totally different numbers. So D doesn't work out, 29 but B does work making be our best answer.