# Model with function combination

Given two basic functions that model a real-world situation, combine them using the appropriate arithmetic operation in order to model a more complex situation.

### Problem

Scarlett sells designer ponchos. The revenue, R, she makes from selling a batch of n ponchos is given by the function R, left parenthesis, n, right parenthesis, equals, 20, n, and the expenses, E, that she incurs from producing a batch of n ponchos is given by the function E, left parenthesis, n, right parenthesis, equals, 10, dot, square root of, n, end square root.
Let P be the total profit Scarlett makes from producing and selling a batch of n ponchos.
Write a formula for P, left parenthesis, n, right parenthesis in terms of R, left parenthesis, n, right parenthesis and E, left parenthesis, n, right parenthesis.
space, P, left parenthesis, n, right parenthesis, equals
Write a formula for P, left parenthesis, n, right parenthesis in terms of n.
space, P, left parenthesis, n, right parenthesis, equals
Get 3 answers correct in a row