A certain list consists of 21 different numbers. If n is in the list and n is 4 times the average(arithmetic mean) of the other 20 numbers in the list, then n is what fraction E of the sum of the 21 numbers in the list?	Choose the correct option
A) 1/20
B) 1/6
C) 1/5
D) 4/21
E) 5/21
This is how I used to calculate which I think works pretty well:   if you let the average of the 20 other numbers equal a, can you write this equation for sum of the list (S)   n + 20a = S   the question tells us that   n = 4a   plug this back into the first equation and you get that the sum is 24a   4a + 20a = 24a   therefore fraction E of n to the total would be   4a/24a or 1/6   answer 1/6 4  + 20= 
<gadget id="calculator"> 4  + 20</gadget>
<output>24</output>
24a   therefore fraction E of n to the total would be   4a/24a or 1/6   answer 1/6
<result>B</result>
A certain list consists of 21 different numbers. If n is in the list and n is 4 times the average(arithmetic mean) of the other 20 numbers in the list, then n is what fraction E of the sum of the 21 numbers in the list?