Write a method that returns the "hopping sum". This is found by adding a sequence of numbers that starts with 'first' and goes up by 'hop' a total of 'howMany' times. For example, if 'first' is 10, 'hop' is 3, and 'howMany' is 4, you would obtain the answer by adding: 10+13+16+19+22 which equals 80. Look at the test data for additional examples.