Set S contains exactly 10 numbers and has an average (arithmetic mean) of 6.2. If one of the numbers in Set S is increased by 3, while all other numbers remain the same, what is the new average of Set S?
Choose the correct choice from the following:
A) 6.5
B) 6.7
C) 6.8
D) 6.85
E) 6.9

Rationale: "old set s - total is avg * no of elements = 6.2 * 10 = 62 if one number is increased by 3 then total increased to 62 + 3 = 65 new avg - 65 / 10 = 6.5 . hence answer is a ."
Answer: A