Five years ago the average of the ages of A and B was 20 years and now the average of the ages of B and C is 48 years. What will be the age of the B ten years hence?  Pick.
A) 45 years  B) 55 years  C) 57 years  D) we cannot determined  E) None of these
Let the present ages of A, B and C be a, b and c respectively.   Given, [(a - 5) + (b - 5)] / 2 = 20 =&gt; a + b = 50 --- (1)   (b + c)/2 = 48 =&gt; b + c = 96 --- (2)   From (1) and (2), we cannot find b.   ANSWER:we cannot determined
<result>D</result>
Five years ago the average of the ages of A and B was 20 years and now the average of the ages of B and C is 48 years. What will be the age of the B ten years hence?