The average marks of 30 students in a class is 100. But a student mark is wrongly noted as 70 instead of 10 then find the correct average marks? Pick one:  A) 78  B) 82  C) 98  D) 91  E) 85

Rationale: "correct avg marks = 100 + ( 10 - 70 ) / 30 avg = 100 - 2 = 98 answer is c"
Answer: C