Which is better investment: 11% stock at 143 or 93/4 % stock at 117?

Answer: Option B

$$\begin{array}{rl}& \text{Let}\text{investment}\text{in}\text{each}\text{case}\text{be}\\ & Rs.\left(143\times 117\right)\\ & \text{Income}\text{in}{\text{1}}^{\text{st}}\text{case}\\ & =Rs.\left(\frac{11}{143}\times 143\times 117\right)\\ & =Rs.1287\\ & \text{Income}\text{in}{\text{2}}^{\text{nd}}\text{case}\\ & =Rs.\left(\frac{39}{4\times 117}\times 143\times 117\right)\\ & =Rs.1394.25\\ & \text{Clearly,}9\frac{3}{4}\%\text{stock}\text{at}117\text{is}\text{better}\end{array}$$