A travel agency will plan a group tour for groups of size 25 or larger. If the group contains exactly 25 people, the cost is $290 per person. If each person's cost is reduced by $10 for each additional person above the 25, then the revenue is given by the equation shown below, where x is the number of additional people above 25.R(x) = (25 + x)(290 − 10x)Find the marginal revenue if the group contains 30 people.

The marginal profit in souls that Freddy Krueger makes from haunting nightmares, x, can be modeled by dP dx = 8x + 20 Find the profit function P if from 2 nightmares, Freddy harvested 60 souls.

A factory produces ceramic soap dishes. Suppose the daily cost (in dollars) to run the factory on a day when x soap dishes are produced is given by C(x) = 18x0.6 + 220. a. Find the marginal cost function.     b. Find the marginal cost when x = 100. Round to two decimal places.   c. Write a sentence or two explaining the meaning of the value you found in part b.

Suppose the function f(x) = 9.09x represents the number of Chinese yuan equivalent to x U.S. dollars and the function g(y) = 0.10y represents the number of British pounds equivalent to y Chinese yuan. a. Write a composite function that represents the number of British pounds equivalent to x U.S. dollars. b. Find the value in British pounds of an item that costs 25 U.S. dollars. a. The composite function is (fog)(x) = (Simplify your answer. Round es as needed.) (gof)(x) (fog)(x)