3. Two cereal companies, A and B, find that the number of people who will buy one of their products in the first month that it is introduced is linearly related to the amount of money they spend on advertising. If company A spends $40, 000 on advertising, then 100, 000 boxes of cereal will be sold, and if it spends $60, 000, then 200, 000 boxes will be sold. However, if company B spends $40, 000 on advertising, then 135, 000 boxes of cereal will be sold. For both companies, the number of boxes of cereal sold increases by the same amount for each additional $1, 000 they spent on ad- vertising. How much advertising does each company need to sell 300, 000 boxes of cereal? [8 marks]