If the arithmetic mean of p and q is 10 and the arithmetic mean of q and r is 24, what is the value of r-p?	Options.
A) 28  B) 10  C) 30  D) 40  E) 5
28rithmetic mean expression for p and q:   (p+q)/2=10 ; p+q=20 ----eq1   28rithmetic mean expression for q and r:   (q+r)/2=20 ; q+r=48 ----eq2   Subtracting eq1 from eq2 we get: r-p=28   Hence, the correct answer is 28
<result>A</result>
If the arithmetic mean of p and q is 10 and the arithmetic mean of q and r is 24, what is the value of r-p?