Can someone help me to solve this exercise? From:Question 13 to 17

15. The grade scale is stored in the Grades worksheet. Before calculating students final grades, create a named range to use in the formula. a. Click the Grades sheet tab. b. Select cells B4:C8. c. Type GradeScale in the Name box. d. Press ENTER. 16. Now you are ready to create a lookup formula to display each students final letter grade. a. Return to the Scores sheet, and click cell AE10. b. On the Formulas tab, in the Function Library group, click the Lookup & Reference button, and select VLOOKUP. c. Click cell AD10 to enter it in the Lookup_value argument box. d. Type GradeScale in the Table_array argument box. e. The rates are located in the second column of the lookup table. Type 2 in the Col_index_num argument box. f. In this case, you do not want to specify an exact match, as the percentage grades do not match the grade scale percentages exactly. An approximate match will return the correct letter grade. g. Click OK. The completed formula should look like this: =VLOOKUP(AD10,GradeScale,2) h. Fill down for all students. Use any method you want. 17. Before closing the project, check your workbook for errors. a. On the Formulas tab, in the Formula Auditing group, click the Error Checking button. b. If errors are found, use the error checking skills learned in this chapter to find and fix the errors.