A shopkeeper purchased 70 kg of potatoes for Rs.420 And sold the whole lot at the rate of Rs. 6.50 per kg. What Will be his gain percent ?

\par C.P. of 1 kg = \par Rs.(\frac{420}{70})  = \par Rs. 6

\par S.P. of 1 kg = \par Rs. 6.50

\par Gain\% =  (\frac{0.50}{6}\times 100)\% = \frac{25}{3}\% = 8\frac{1}{3}\%