Question 782492
The average (arithmetic mean) of r, s, x and y is 8, 

{{{(r+s+x+y)/4=8}}}
{{{r+s+x+y=32}}}.......eq.1
and the average of x and y is 4
{{{(x+y)/2=4}}}

{{{(x+y)=8}}}.....eq.2..substitute in eq.1

{{{r+s+(x+y)=32}}}.......eq.1

 {{{r+s+(8)=32}}}

{{{r+s =32-8}}}

{{{r+s =24}}}

the arithmetic mean  will be {{{(r+s)/2 =12}}}

so, your answer is {{{d}}}) {{{12}}}