It's no going to be the exact number, it's 0.33, just divide 1/3 :) hope it helps you
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.