Answer:
Option C
Explanation:
Suppose she borrowed Rs. $x$ at $7\frac{1}{2}\%$ p.a. and Rs. $(24000-x)$ at $9\%$ p.a.
I gives, total interest = Rs. $2025$.
$\therefore$ $\left(x\times 1\times\frac{15}{2}\times\frac{1}{100}\right)$ $+\left\{(24000-x)\times 1\times\frac{9}{100}\right\}$ $=2025$.
This gives $x$.
II gives interest on Rs. $(24000-x)$ $=2\times$ (interest on Rs. $x$).
$\Rightarrow (24000-x)\times\frac{9}{100}\times 1$ $=\left(2\times x\times\frac{15}{2}\times\frac{1}{100}\right)$
This gives $x$.
Thus I as well as II are suffficient to answer the question.
$\therefore$ Correct answer is (C).