Which is better investment: 11% stock at 143  or  $$9\frac{3}{4}$$% stock at 117?

Solution(By Examveda Team)

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