The circulation for magazine P in 1961 was 4 times the average (arithmetic mean) yearly circulation for magazine P for the years 1962-1970. What is the ratio of the circulation in 1961 to the total circulation during 1961-1970 for magazine P ?  Choose the correct choice from the following options.
A) 2 / 7 B) 5 / 7 C) 3 / 7 D) 4 / 7 E) 1 / 7

Rationale: "there are 9 years from 1962 - 1970 , inclusive . let ' s say the average circulation every year between 1962 - 1970 inclusive is x . so the total circulation is 9 x from 1962 - 1970 , inclusive . in 1961 , the circulation is 4 x . so total circulation for 1961 - 1970 is 4 x + 9 x = 13 x . ratio of circulation in 1961 to total circulation during 1961 - 1970 is 4 x to 14 x or 4 / 14 = 2 / 7 answer : a"
Answer: A