index.js

/*
 * The moneySaver function takes in student info and returns a string
 * that details the amount of money they would save on gas if they 
 * switched to the Ford Fusion Hybrid.
 *
 * @param {string} studentName - The name of the student
 * @param {number} cityMpg - The city miles per gallon their current car gets
 * @param {number} highwayMpg - The highway miles per gallon their current car gets
 * @param {number} cityMiles - The number of personal city miles they drive in one year
 * @param {number} highwayMiles - The number of personal highway miles they drive in one year
 * @param {number} days - The number of days that student drives per year
 *
 * @return {string} Information about a user's annual gas savings
 */
 
function moneySaver(studentName, cityMpg, highwayMpg, cityMiles, highwayMiles, days){
    // Savings will store the result of all the calculations
    var savings = 0
    var answer
    // Variables: mpg for the Ford Fusion Hybrid
    
    // Store the value of running the calculateCostOfGas function for each
    // car. 

    // Calculate savings

    // Construct answer

    // Return answer
    return answer
}

/*
 * The calculateCostOfGas function 
 *
 * @param {number} days
 * @param {number} cityMpg
 * @param {number} highwayMpg 
 * @param {number} cityMilesPerDay
 * @param {number} highwayMilesPerDay
 *
 * @return {number} totalCost
 */

function calculateCostOfGas(){
    var costPerGallon = 2.95
    var totalCost = 0
    
    // Do all calculations here
    
    
    
    // Good luck!
    
    return totalCost
}