The age of father 10 years ago was thrice the age of his son. Ten years hence, father's age will be twice that of his son. The ratio of their present ages is: Select.
A) 5 : 2
B) 7 : 3
C) 9 : 2
D) 13 : 4
E) 13 : 6
Let the present ages of father and son be x and y years respectively.   Then (x-10) = 3 (y-10) or   3y-x = 20 ------ (1)   and (x+10) = 2 (y+10) or   x-2y = 10 ----- (2)   (1) + (2) -&gt; y = 30   Substituting y = 30 in equation (1) we get x = 70   Ratio of their ages = 70 : 30 or 7:3   ANSWER:7 : 3
<result>B</result>
The age of father 10 years ago was thrice the age of his son. Ten years hence, father's age will be twice that of his son. The ratio of their present ages is: