A shopkeeper purchased 70 kg of potatoes for Rs. 420 and sold the whole lot at the rate of Rs. 6.40 per kg. What will be his gain percent?  Pick one:
A) 8 1/7 % B) 2 1/3 % C) 6 2/3 % D) 8 1/8 % E) 8 1/9 %
C.P. of 1 kg = 420/70 = Rs. 6   S.P. of 1 kg = Rs. 6.40   Gain % = 0.40/6 * 100 = 20/3   = 6 2/3 %   Answer:6 2/3 %
<result>C</result>
A shopkeeper purchased 70 kg of potatoes for Rs. 420 and sold the whole lot at the rate of Rs. 6.40 per kg. What will be his gain percent?