The respective ages of father and his son are 47 and 16 years. In how many years will the father be twice as old as his son ?	Choose the correct choice from the following choices:  A) 19 years  B) 9 years  C) 10 years  D) 15 years  E) 12 years
Suppose x years later the father will be twice as old as his son.   x + 47 = 2 (x + 16)   x = 47 - 32= 
<gadget id="calculator">47 - 32</gadget>
<output>15</output>
15 years   answer : 15 years
<result>D</result>
The respective ages of father and his son are 47 and 16 years. In how many years will the father be twice as old as his son ?