If A father said to his elder son, "I was as old as you are at the present at the time of your birth". If the father's age is 25 years now, what was the son's age four years back?  Answers:
A) 7.5
B) 8.5
C) 9
D) 9.5
E) 10
Let son's present age be a years. Then,   (25−a)=a   ⇒2a=25   ⇒a=25/2= 
<gadget id="calculator">25/2</gadget>
<output>25/2 = around 12.5</output>
12.5   Son's age 4 years back=12.5-4= 
<gadget id="calculator">12.5-4</gadget>
<output>8.5</output>
8.5   ANSWER:8.5
<result>B</result>
If A father said to his elder son, "I was as old as you are at the present at the time of your birth". If the father's age is 25 years now, what was the son's age four years back?