A certain sum amounts to ₹9243.20 in $$1\frac{1}{2}$$ years at 4% p.a. simple interest. What will be the simple interest on the same sum for $$7\frac{1}{2}$$ years at 8% per annum?

Let the sum be Rs. $$x$$ at 4% simple interest and for $$t=\frac{3}{2}$$ years

Simple Interest = $$\frac{P\times R\times T}{100}$$

=> $$\frac{x\times4\times3}{2\times100}+x=9243.20$$

=> $$\frac{3x}{50}+x=9243.20$$

=> $$x=9243.20\times\frac{50}{53}=Rs.$$ $$8720$$

$$\therefore$$ S.I. on same sum at 8% for $$t=\frac{15}{2}$$ years

= $$\frac{8720\times8\times15}{2\times100}$$

= $$87.2\times60=Rs.$$ $$5232$$

=> Ans - (C)