Question

During a fair, Reeta gains Rs.2 on each pen and loses Rs.1 on each pencil. She sells 50 pens and some pencils, losing Rs.15 in all. How many pencils does she sells?

Answer 1

Dear Student,
$$\begin{gathered} \mathrm{Gain}\mathrm{on}\mathrm{each}\mathrm{pen}=\mathrm{Rs}.2 \\ \mathrm{And}\mathrm{loss}\mathrm{on}\mathrm{each}\mathrm{pencil}=\mathrm{Rs}.1 \\ \mathrm{Gain}\mathrm{on}50\mathrm{pens}=50\times 2=\mathrm{Rs}.100 \\ \mathrm{Let}\mathrm{the}\mathrm{number}\mathrm{of}\mathrm{pencils}\mathrm{she}\mathrm{sells}\mathrm{be}\mathrm{x}. \\ \mathrm{Amount}\mathrm{of}\mathrm{money}\mathrm{lost}\mathrm{on}\mathrm{x}\mathrm{pencils}=\mathrm{Rs}.\mathrm{x}\times 1=\mathrm{Rs}.\mathrm{x} \\ \mathrm{Net}\mathrm{loss}=\mathrm{Rs}.15 \\ \Rightarrow \mathrm{x}-100=15 \\ \Rightarrow \mathrm{x}=100+15=115 \\ \mathrm{So}\mathrm{total}\mathrm{number}\mathrm{of}\mathrm{pencils}=115 \end{gathered}$$
Regards