• # question_answer A vendor sells lemons at 5 for a rupee gaining 40%. How many did he buy for a rupee? A)  6                   B)  7    C)  8                    D)  10

(b): Let C.P be 'x' per lemon S.P = 1/5 (for one lemon) $Gain\,%=\frac{\frac{1}{5}-x}{x}\times 100%=40%$ $\Rightarrow \frac{\frac{1}{5}-x}{x}=\frac{2}{5}$ $\Rightarrow 1-5x=2x$ $\Rightarrow 1=7x\Rightarrow x=\frac{1}{7}.$ $\Rightarrow$ C.P OF 7 lemons = 1 rupees.