I need help with this not really good at this

Sharon had some insider information about a corporate takeover. she unintentionally informed a friend, who immediately bought the stock in the target corporation. the takeover occurred and the friend made a substantial profit from buying and selling the stock. the friend told sharon about his stock dealings, and gave her a pearl necklace because she "made it all possible." the necklace was worth $10,000, but she already owned more jewelry than she desired.

Which of the following is an example of a positive externality? a. promoting generic drugs would benefit people. b. a lower inflation rate would benefit most consumers. c. compulsory flu shots for all students prevents the spread of illness in the general public. d. singapore has adopted a comprehensive savings plan for all workers known as the central provident fund.

Assume that a local bank sells two services, checking accounts and atm card services. the bank’s only two customers are mr. donethat and ms. beenthere. mr. donethat is willing to pay $8 a month for the bank to service his checking account and $2 a month for unlimited use of his atm card. ms. beenthere is willing to pay only $5 for a checking account, but is willing to pay $9 for unlimited use of her atm card. assume that the bank can provide each of these services at zero marginal cost.refer to scenario 17-5. if the bank is unable to use tying, what is the profit-maximizing price to charge for a checking account