So let's make two equations based off the information we are given:
Let B be equal to Ben's current age
Let I be equal to Ishann's current age


The second equation can be expanded to:

Now using the process of elimination:
B - 6 = 6I - 36
B = 4I *subtraction
-6 = 2I -36
Now solve for I:
-6 = 2I - 36
30 = 2I
I = 15
Therefore Ishann is 15 years old, making Ben 60.
Hope this helps!