The average marks of 30 students in a class is 60. But a student mark is wrongly noted as 90 instead of 15 then find the correct average marks?	Choose the correct choice from the following choices:
A) 55.65 B) 57.5 C) 62.5 D) 45.25 E) 50

Rationale: correct avg marks = 60 + ( 15 - 90 ) / 30 avg = 60 - 2.5 = 57.5 answer is b
Answer: B