Require Help on updation of sheets

Hi Everyone !

My name is tippu, i need a simple solution to one of my excel problem. i have a excel workbook containing 3 sheets. the first sheet contains marks of all the 10 students with there roll numbers in test 1. the second sheet contains the marks obtained by the failed students in test 2. i need a updated data in sheet 3 of all the students, showing the marks obtained by the passed students in test 1 and also the updated marks obtained by the failed students in test 2. can anybody post a solution for this. please find a attached sample copy.

Thank you valady it is partially solved ....
Here in thatng c c worksheet, Roll No in the roll number of the student, T represents the total marks, C represents constant value (4 for pass , 0 for fail). in test 1 who ever is having c value 4 will not write test 2, and in the final sheet he should have test 1 value in T coloum, in another case where student has failed in test 1 he will have c value as 0, he will be writing test 2 depending on pass or fail in test 2 again he will have c value as 4 or 0. in final sheet in need updated result from test 1 and test 2.
Finallyy the solution what you have provided actulally giving the added marks of test 2 in the T coloum, where as C coloum is perfectly correct. i need the updated marks in T coloum. (if he has passed test 1 , the T coloum of the final sheet , should show test 1 marks, if he has failed then the T coloum of the final sheet should show test 2 marks).
once again thanks !