Question

The number P of British pounds you can get from a bank is a linear function of the number D of American dollars you pay. An American tourist arriving at Heathrow airport in England went to a banking window at the airport and gave the teller 70 American dollars. She received 46 British pounds in exchange. In this exercise, assume there is no service charge for exchanging currency.

What is the rate of change, or slope, of P with respect to D? (Note: You need two values to calculate slope, but you were given only one. If you think about it, you know the other value. How many British pounds can you get for zero American dollars? Round your answer to five decimal places.)

pounds per dollar

Explain in practical terms what this number means.
This means each dollar is worth  
pound.

(b) A few days later, the American tourist went to a bank in Plymouth and exchanged 130 American dollars for British pounds. How many pounds did she receive? (Round your answer to two decimal places.)
£  

(c) Upon returning to the airport, she found that she still had £11.84 in British currency in her purse. In preparation for the trip home, she exchanged that for American dollars. How much money, in American dollars, did she get? (Round your answer to two decimal places.)

Answer 1