Answers

2014-07-31T22:51:42+08:00
Let x = number of years when the father is twice as old as his son
thus
         42 + x = 2(12+x)
          x =  42-24 =18
   in 18 years time
0
2014-07-31T23:28:05+08:00
30 years????????????????????????????????????????????????
0