A certain sum of money is invested for 6 years in Scheme A which offers simple interest at a rate of 18.5% p.a. The simple interest obtained from Scheme A is equal to the amount obtained when 3/4 times the same sum of money is invested in a different scheme B that also offers Simple interest. If the sum is invested for 4 years in Scheme B. What is the rate of interest (p.a.) offered by Scheme B ?