A shopkeeper has 280 kg of apples. He sells 40% of these at 30% profit and remaining 60% at 30% profit. Find his % profit on total.  Pick one:
A) 24 % B) 25 % C) 26 % D) 28 % E) 30 %

Rationale: "if the total quantity was 100 then 40 x 30 % + 60 x 30 % = 30 this profit will remain same for any total quantity unless the % of products remains the same . hence ' e ' is the answer"
Answer: E