The average of the marks of 10 students in a class is 40. If the marks of each student are doubled, find the new average?	Pick.
A) 78
B) 56
C) 80
D) 27
E) 40

Rationale: "sum of the marks for the 10 students = 10 * 40 = 400 . the marks of each student are doubled , the sum also will be doubled . the new sum = 400 * 2 = 800 . so , the new average = 800 / 10 = 80 . answer : c"
Answer: C