Calculating Parking Fees
Your code should be as similar to the spec as possible so:

else if (numHours &gt;19)
     garageCost = 10;


Should be removed and you should add:

return Math.min(garageCost, 10)


My final version is:

public static double calculateCharges (double numHours)
{
    if (numHours &lt;= 3)
    {
         return 2;
    }
    double garageCost = 2.0 + 0.5 * (numHours - 3);
    return Math.min(garageCost, 10);
}