A student obtained 75%, 80% and 85% in three subjects, if the marks of another subject are added then the number can’t be less than

A) 60%

C) 80%

B) 70%

D) None of these

Total marks of 3 subject = 75 + 80 + 85 = 240 out of 300 at least average marks ≥ 240 out of 400.

Considering worst case possibility, mark of fourth subject = 0

Average of marks ≥ (240/400) × 100 = 60%

∴ Average will always be more than 60%.