Calculate the average of all the numbers between 7 and 49 which are divisible by 6.  Choose the correct choice from the following choices
A) 20  B) 18  C) 19  D) 15  E) 30

Rationale: "explanation : numbers divisible by 6 are 12 , 18,24 , 30,36 , 42,48 , average = ( 12 + 18 + 24 + 30 + 36 + 42 + 48 , ) / 7 = 210 / 7 = 30 answer : e"
Answer: E