Question

Find C.P if $S.PisRs42andProfit=5\%$

Answer 1

As it is given that $S.PisRs42andProfit=5\%$

we know that $Profit\%=\frac{Profit}{C.P}\times 100---\left(\mathrm{i}\right)$

Let the $C.PbeRsX$

Now, $Profit=S.P-C.P=Rs(42-x)$

Putting in equation (i)

$$\begin{gathered} \Rightarrow 5=\frac{\left(42-x\right)}{x}\times 100 \\ \Rightarrow \frac{5}{100}=\frac{\left(42-x\right)}{x} \\ \Rightarrow \frac{1}{20}=\frac{\left(42-x\right)}{x} \\ \Rightarrow x=20\left(42-x\right) \\ \Rightarrow x=840-20x \\ \Rightarrow x+20x=840 \\ \Rightarrow 21x=840 \\ \Rightarrow x=\frac{840}{21}=40 \end{gathered}$$

Hence $\mathrm{C}.\mathrm{P}\mathrm{is}\mathrm{Rs}40$