Which of the following scenarios BEST illustrates the role of money as a medium of exchange? A
Jane writes a $600 check to pay her rent.
B
Jane has a $500 balance on her credit card.
C
Jane puts 5% of her income into savings each month.
D
Jane uses her investments as collateral for a business loan.

When a company produces and sells x thousand units per week, its total weekly profit is p thousand dollars, where upper p equals startfraction 800 x over 100 plus x squared endfraction . the production level at t weeks from the present is x equals 4 plus 2 t. find the marginal profit, startfraction dp over dx endfraction and the time rate of change of profit, startfraction dp over dt endfraction . how fast (with respect of time) are profits changing when tequals8?