The average score in an examination of 10 students of a class is 60. If the scores of the top five students are not considered, the average score of the remaining students falls by 5. The pass mark was 40 and the maximum mark was 100. It is also known that none of the students failed.
If each of the top five scorers had distinct integral scores, the maximum possible score of the topper is
Number of students = 10
Average score of 10 students = 60
Total score of 10 students = 60*10 = 600
Average score of bottom 5 students = 55
Total score of bottom 5 students = 55*5 = 275
Total score of top 5 students = 600 - 275 = 325
To maximize the score of the topper, score of remaining 9 students need to be minimized.
Possible scores of bottom 5 students = {55,55,55,55,55}
Let the score of the topper be x.
Possible scores of top 5 students to maximise topper's score = {55,56,57,58,x}
55+56+57+58+x = 325
x = 99
The maximum possible score of the topper = 99
IMO C