I = PRT/100
Let Rate of Interest = X
Interest in Case of Rakesh = (20000 x 5.5 x X)/100
Interest in Case of Dinesh = (25000 x 4 x X)/100
Total Interest Recieved = 19950 = (20000 x 5.5 x X)/100 + (25000 x 4 x X)/100 =(210,000 x X)/100
=> 19950 = 2100X
=> X = 9.5 %