The cost in dollars to produce x cups of lemonade is represented by the function c(x) = 10 + 0.20x. the revenue in dollars earned by selling x cups of lemonade is represented by the function r(x) = 0.50x. what is the minimum number of whole cups of lemonade that must be sold for the revenue to exceed the cost?

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations