600 + 400 = 1000
200 + 400 = 600
400 + 200 = 600
200 + 400 = 600
1,500
4,700.
0.6667
400
600.
It is 400 because 150% of 400 = 600
400
If you mean CD plus DC then in Roman numerals they add up to M meaning 400 plus 600 = 1000
1000 milliliters :D or 100 cantiliters or 1 liter