Question

A vendor purchased bananas at Rs 16 per dozen and sold them at 10 for Rs 18. Find his gain or loss per cent.

Answer 1

$$\begin{gathered} \mathrm{SP}\mathrm{of}10\mathrm{bananas}=\mathrm{Rs}.18 \\ \mathrm{SP}\mathrm{of}1\mathrm{banana}=\frac{18}{10}=\mathrm{Rs}.\frac{9}{5} \\ \mathrm{CP}\mathrm{of}12\mathrm{bananas}=\mathrm{Rs}.16 \\ \mathrm{CP}\mathrm{of}1\mathrm{banana}=\mathrm{Rs}\frac{16}{12}=\mathrm{Rs}.\frac{4}{3} \\ \mathrm{Since}\mathrm{SP}>\mathrm{CP},\mathrm{there}\mathrm{is}\mathrm{a}\mathrm{gain}. \\ \mathrm{Now},\mathrm{gain}=\mathrm{SP}-\mathrm{CP} \\ =\frac{9}{5}-\frac{4}{3} \\ =\mathrm{Rs}.\frac{7}{15} \\ \therefore \mathrm{Gain}\mathrm{percentage}=(\frac{{\displaystyle \frac{7}{15}}}{{\displaystyle \frac{4}{3}}}\times 100)\% \\ =(\frac{7}{15}\times \frac{3}{4}\times 100)\% \\ =35\% \end{gathered}$$