Sachin lent out Rs 60000 in two parts, first at 4% and the second at 10% interest. The yearly average interest comes out to be 6.4%. What are the amounts (in Rs) that were lent at 4% and 10% respectively?

Let sum lent for 4% = Rs. $$100x$$ and sum lent for 10% = Rs. $$(60,000-100x)$$

Time period = 1 year and rate of interest = 6.4%

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

= $$\frac{60,000\times6.4\times1}{100}=Rs.$$ $$3840$$

According to ques,

=> $$\frac{100x\times4\times1}{100}+\frac{(60000-100x)\times10\times1}{100}=3840$$

=> $$4x+(600-x)\times10=3840$$

=> $$4x+6000-10x=3840$$

=> $$6x=6000-3840=2160$$

=> $$x=\frac{2160}{6}=360$$

$$\therefore$$ Amount lent at 4% = $$100\times360=Rs.$$ $$36,000$$

Amount lent at 10% = $$(60,000-36,000)=Rs.$$ $$24,000$$

=> Ans - (C)