In this exercise, you modify the Grade Calculator application from this lesson. Use Windows to make a copy of the Grade Solution folder. Rename the copy Grade Solution-Intermediate. Open the Grade Solution (Grade Solution.sln) file contained in the Grade Solution-Intermediate folder.

a. Open the CourseGrade.vb file. Modify the DetermineGrade method so that it accepts the maximum number of points that can be earned on both tests. For an A grade, the student must earn at least 90% of the total number of points. For a B, C, and D grade, the student must earn at least 80%, 70%, and 60%, respectively. If the student earns less than 60% of the total points, the grade is F. Make the appropriate modifications to the class, and then save the solution.

b. Add a label control and a text box to the form. Change the label control’s Text property to “&Maximum points” (without the quotation marks). Change the text box’s name to txtMax.

c. Open the form’s Code Editor window. The text box should accept only numbers and the Backspace key. The maximum number allowed in the text box should be 400. Each list box should display numbers from 0 through 200. Make the necessary modifications to the code, and then test the application appropriately.