Answer:
Opportunity cost for the money Rachel invests in the bookstore is $7500
Step-by-step explanation:
Whenever a choice has to be made between two alternatives. One has to be selected and the other has to be foregone. Opportunity cost is the cost of alternative foregone.
If Rachel is thinking of starting a bookstore rather than investing that money in stocks than he will have to forgo the return he will get by investing in stocks.
so Return on stock will be 10%of $75000
i.e $7500
$7500 is the opportunity cost of starting a bookstore.