["Find total units: 3 + 8 = 11 units. Each unit = 990 / 11 = 90 people.","Thrill = 3 x 90 = 270. Teens:adults = 5:4 so adults (thrill) = 4/9 x 270 = 120.","Family = 8 x 90 = 720. Teens:adults = 2:7 so adults (family) = 7/9 x 720 = 560. Total adults = 680, total teens = 310. Difference = 680 - 310 = 370."]