Review the excerpt from the code book. if eve parks a van outside alice's house, she can use sensitive tempest equipment to identify each individual keystroke that alice makes on her computer. this would allow eve to intercept the message as it is typed into the computer, before it is encrypted. to defend against tempest attacks, companies are already supplying shielding material that can be used to line the walls of a room to prevent the escape of electromagnetic signals. in this excerpt, the author explains

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