10.) 1991 - 1891 = 100 yrs.....4500(100) = 450,000
population in 1991 was 900,000. population in 1891 was 900,000 - 450,000 =
450,000
12.) cost 3.80 and sold for 6.....so there is a profit of 6 - 3.80 = 2.20 per box.
class 1 : 150(2.20) = 330
class 2 : 175(2.20) = 385
class 3 : 225(2.20) = 495
(330 + 385 + 495) / 2 = 1210/2 = 605 <== each charity received 605
