[Video] Q30: A researcher surveyed 200 adults selected at random from the city of aldley and 300 adults selected at random from the suburbs of aldley. each person surveyed was asked whether he or she owns a car. some of the results are shown in the partially completed table below.

Explanation for Question 30 From the Math (Calc) Section on the 2019 May Sat

So question 30 tells us that the researcher found that an adult 2 survey in the suburbs of Ollie is twice as likely to own a car 3 as an adult surveyed in the city of boldly of the following, 4 which could be the value of X. So let's start by finding how likely 5 it is to, uh, to own a car in the city of Ollie. 6 And the fraction here is 80, 7 over 280 out of the 200 people in the city 8 of Ollie own a car. And that's twice as likely, 9 or I'm sorry, half as likely to occur as owning a car in the 10 suburbs of Olli, which means that we need to multiply it by two, 11 before we set it equal to X over 300, 12 which is the amount of people who own a car in the suburbs of 13 all the week. And I got that information from those two points on the 14 table. So after that, 15 we can then sell for X. So this becomes one 60 over 200 16 is equal to X. Over 300 or simplified for 17 over five is equal to ax over 300. 18 Then we can cross multiply and write this as five X is equal to 19 1200. I just multiplied four by 300 there 20 and then divide by five defined that X is 21 two, 240. 22 So the answer here is.