The total capacity of 2 identical kettles is the same as the total capacity of 5 identical jugs. If 17.6 litres of water are needed to fill up 12 jugs and 4 kettles completely, what is the capacity of a jug in millilitres?
The total capacity of 4 kettles is 17.6 litres*1000 ml/1 litre = <<17.6*1000=17600>>17600 ml.
The capacity of 1 kettle is 17600 ml/4 = <<17600/4=4400>>4400 ml.
The capacity of 2 kettles is 2 * 4400 ml = <<2*4400=8800>>8800 ml.
The total capacity of 5 identical jugs is 17600 ml - 8800 ml = <<17600-8800=8800>>8800 ml.
The capacity of 1 jug is 8800 ml/5 = <<8800/5=1760>>1760 ml. Answer: \boxed{1760}.