Explanation for Question 9 From the Math (Calc) Section on the Official Sat Practice Test 6
Question nine as a word problem. And it reads the total area of a 2 coastal city is 92.1 square miles of which 11.3 3 square miles is water. If the city had a population of 621,000 4 people in the year 2010, which of the following is closest to the population 5 density in people per square mile of land area of the city. 6 At that time, it's like I said, 7 this is a word problem. And sometimes it can be intimidating to look at 8 this big, big paragraph of words and translate that into, 9 um, an equation or into numbers that are our answer choices. 10 So let's try and break it down to make it a little more manageable. 11 The first thing that we notice is that it's asking us for the population 12 density in people per square mile of land area. 13 In this first part of the question, it mentions that the total area is 14 92.1 square miles of which 11.3 is water. 15 So to get the square miles of land area, 16 we need to do the total area minus the water area, 17 essentially. So that's going to be 92.1 square miles minus 18 11.3. So that will get us to 90.1 minus 11.3 19 is equal to 80.8 square miles of 20 land. All right. 21 So with that, we can solve for our answer actually, 22 because we're just looking for people per square mile of land area. 23 So we know that we have 621,000 people 24 over 80.8 square miles 25 of land. So now we can just plug that into our calculator and we've 26 got 621,000 divided by 80.8. 27 And that gets you to 7,686 28 people per square mile. 29 All right. So going through our answer choices, 30 we can pick B as the best one. 31 This is the closest to our answer choice. 32 7,686 is approximately equal to 7,609.