Ben is 12 years older than ishaan. ben and ishaan first met two years ago. three years ago, ben was 4 times as old as ishaan?

The first statement means: 
 
b=i+12,
 
The third statement means:
 
b-3=4(i-3),

b-3=4i-12

b=4i-9

Using the value for b from the first statement in the third statement gives you: 

i+12=4i-9

-3i=-21

i=7:   and since b=i+12

b=19

So Ben is 19 and Ishaan is 7.