[Video] Q19: Graphene, which is used in the manufacture of integrated circuits, is so thin that a sheet weighing one ounce can cover up to 7 football fields. if a football field has an area of approximately 1 1/3 acres, about how many acres could 48 ounces of graphene cover?

Explanation for Question 19 From the Math (Calc) Section on the Official Sat Practice Test 3

All right. So for number 19, we see, we have graph theme, 2 which is use to manufacturing, integrated circuits, 3 or told that it. So then that a sheet weighing one ounce can cover 4 up to seven football fields. Now, 5 if a football field has an area of 1.1, 6 three acres, how many acres could 48 ounces of graphing cover? 7 And so this is really a proportions problem. The way we can figure that 8 out is because we have two types of information, 9 right? We have information about acres and we have information about ounces of graphing. 10 And then we actually have one complete set of information. 11 So we have one complete set of information, 12 and then we have a half set of information. And what I mean by 13 complete set and half set is that first we know that one ounce 14 covers seven football fields and football fields, 15 haven't area of one and a third acres. 16 Right? So that essentially means that, 17 well, first let some one in one 30, 18 let's create that as a fraction. So we've got one third plus one, 19 right? We can just kind of round that off to 1.3, 20 three, three. And so we know that one ounce can 21 do seven football fields. So seven times at 1.3, 22 three, three, that's how much it could cover, 23 right? Cause that's going to be the area of seven football fields. 24 And now we want to know right there actually there's our complete set of 25 information. And then we want to know, 26 um, how many 48 ounces could, 27 could cover. So right now we have 48 ounces, ...