You are a civil engineer who wishes to evaluate whether or not driving to a gas station x miles away where gas is n cents cheaper is a money saver or not. in other words, the problem you wish to solve is, "if i am at station a and it costs $x. xx per gallon, and gas at station b is cheaper and costs $x. xx will i save money by driving x miles to station b to get gas? " since a major goal of this assignment is to gain experience with user written functions, you are required to create a function in addition to the script file. create a function named cost that has gallons of gas purchased and price per gallon as its inputs and returns the total cost as its output.