Answer with Explanation:

B.D. for 3/2 years = Rs. 558.
B.D. for 2 years
= Rs.(558 x 2/3 x 2)

= Rs. 744

T.D. for 2 years = Rs. 600.

Therefore, Sum = B.D. x T.D./ B.D. - T. D. = Rs.( 744 x 600/144)= Rs. 3100.
Thus, Rs. 744 is S.I. on Rs. 3100 for 2 years.

Therefore, Rate = (100 x 744/3100 x 2)% = 12%