The average of the marks of 30 students in a class is 45. If the marks of each student are doubled, find the new average? Choose the correct choice from the following choices:
A) 85
B) 77
C) 33
D) 90
E) 75

Rationale: "sum of the marks for the 30 students = 30 * 45 = 1350 . the marks of each student are doubled , the sum also will be doubled . the new sum = 1350 * 2 = 2700 . so , the new average = 2700 / 30 = 90 . answer : d"
Answer: D