A merchant has 1000 kg of sugar, part of which he sells at a 10% profit and the rest at a 40% profit. He gains 20% on the whole. The quantity sold at 40% profit is:
1
\(543\frac{1}{3} \, \text{kg}\)
2
\(383\frac{1}{3} \, \text{kg}\)
3
\(333\frac{1}{3} \, \text{kg}\)
4
\(443\frac{1}{3} \, \text{kg}\)