A container of chocolates was packed into packed of 250g and 400 g in the ratio 7:2. After selling 12 packets of 250g and 2 packes of 400g, the ratio became 3:1. What was the mass of chocolates in the container at first?
2 + 7 = 9(250 + 400)
= 9 x 650g
= 5850 ÷ 1000
= 5.850kg