A dishonest shopkeeper promises to sell his goods at its cost price but he uses 30% less weight. The profit percent is:

\(40\frac{2 }{5}\)% \(42\frac{6}{7}\)% \(43\frac{5 }{7}\)% \(45\frac{2 }{5}\)%

\(42\frac{6}{7}\)%

Let the price of 1000 gm. = Rs. 100 but he uses 700 gm. instead of 1000 gm. (1000 × 70% = 700 gm.) C.P. of 700 gm. = Rs. 70 S.P. of 700 gm. = Rs. 100 Profit = \(\frac{(100 - 70)}{70}\) × 100 = \(\frac{300}{7}\) = 42\(\frac{6}{7}\)%