# A sum of Rs. 1550 was lent partly at 5% and partly at 8% p.a. simple interest. The total interest received after 3 years was Rs. 300. The ratio of the money lent at 5% to that lent at 8% is:

A. 5 : 8 B. 8 : 5 C. 16 : 15 D. 31 : 6 Answer: Option C
Let the sum lent at 5% be Rs. x and that lent 8% be Rs. (1550 – x). Then, $\begin{array}{l}\left(\frac{x\times5\times3}{100}\right)+\left[\frac{(1550-x)\times8\times3}{100}\right]=300\\ \Leftrightarrow15x-24x+(1550\times24)=30000\\ \Leftrightarrow9x=7200\\ \Leftrightarrow x=800.\\ \therefore\text{ Required ratio }=800:750\\ =16:15\end{array}$