A invested the amount of Rs. 2x/3 at 7.5% p.a. SI for 2 years and B invested the amount of Rs. x/3 at 5% p.a. SI for 3 years. The interest earned by A is 600 more than the interest earned by B.  Find the interest earned by (7x/3)  for 3 years at 15% p.a SI.