In 4 years, harry’s age will be the same as jim’s age is now. in 2 years, jim will be twice as old as harry will be. find their ages now.

The answer to this question would be:
Jim     =6 years
Harry =2 years

To answer this question, you need to translate the description into a  mathematical equation. If H= Harry's ages and J= Jim's ages, then the equation should be look like this:

1. H+4= J
2. (J+2)= 2(H+2)
     J+2= 2H+4
     J= 2H +2

If you put the 1st and 2nd equation together, the result would be:
H+4= J
H+4= (2H +2)
H-2H= 2-4
-H= -2
H=2

After that insert the H value to either 1st or 2nd equation.
H+4= J
2+4=J
J= 6