Urgent!! About Excel

*Please answer all the questions as soon as possible. Thankyou very much^^
1.The following worksheet shows the assessment results of 4 students:
A , B , C , D , E
1)Name , Test1 , Test2 , Exam , Total
2)Chan Man-lun , 56 , 78 , 78
3)Cheung Lai-mei , 89 , 96 , 91
4)Ho Yue-chung , 78 , 45 , 56
5)Law Kun-tin , 90 , 22 , 45
6)-
7)-
8)Weight of Test1 , 0.1
9)Weight of Test2 , 0.2
10)Weight of Exam , 0.7

(a)The values in cells E2, E3, E4, and E5 are calculated by the following mathematical expression:

Test1 × Weight of Test1 + Test2 × Weight of Test2 + Exam × Weight of Exam
These values represent the assessment totals of students.
(i)Write the formula that should be stored in cell E2.
(ii)A student finds the correct value in cell E2. When the formula stored in cell E2 is copied to cells E3, E4, and E5, the figures showing the totals in cells E3, E4, and E5 are wrong. Suggest ONE reason for the error.

(b)Cell E6 is used to show the average of the 4 assessment totals. Write the formula that should be stored in cell E6.

(c)Give ONE advantage of using an electronic spreadsheet, instead of a calculator, to find the assessment result of students.