A wholesaler purchased 7 hair clips for a rupee. How many for a rupee must he sell to get profit of 40%?
Let the required number be x
⇒ 40 = $(\left( {\frac{{7\; \times \;1}}{{x\; \times \;1\;}} - \;1} \right))$ × 100
⇒ 2/5 = 7/x - 1
⇒ 2/5 + 1 = 7/x = 7/5 = 7/x
⇒ x = 5
∴ He has to sell 5 pair of clips for a rupee to get profit of 40%