Richard Gorman is 65 years old and about to retire. He has $420,000 saved to supplement his pension and Social Security and would like to withdraw it in equal annual dollar amounts so that nothing is left after 15 years. How much does he have to withdraw each year if he earns 9 percent on his money? If he earns 9 percent on his money, the amount he will have to withdraw each year is $ . (Round to the nearest cent.)

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?