A certain list consists of 21 different numbers. If n is in the list and n is 6 times the average (arithmetic mean) of the other 20 numbers in the list, then n is what fraction of the sum of the 21 numbers in the list? Select the correct option:
A) 1/20  B) 3/13  C) 1/5  D) 4/21  E) 5/21
series : a1, a2....a20,n   sum of a1+a2+...+a20 = 20*x (x = average)   so, n = 6*x   Hence, a1+a2+..+a20+n = 26x   So, the fraction asked = 6x/26x = 3/13   Answer 3/13
<result>B</result>
A certain list consists of 21 different numbers. If n is in the list and n is 6 times the average (arithmetic mean) of the other 20 numbers in the list, then n is what fraction of the sum of the 21 numbers in the list?