Understand the concept of modelling a real-life situation in a function, and compare graphical models to the real-life of a situation that is given.
Otto is a traveling beach salesman. He sells beach balls for $\$17$ and bags of cotton candy for $\$4$. Every day, he travels along the same beach, and a fisherman gives him a $\$2$ tip. Which of the following expressions represents Otto’s daily profit, in dollars, if he sells $b$ beach balls and $c$ bags of cotton candy?