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 7, while all other numbers remain the same, what is the new average of Set S?  Pick: A) 6.6 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 7 then total increased to 62 + 7 = 69 new avg - 69 / 10 = 6.9 . hence answer is e ."
Answer: E