When an ice box is packed with 10 identical bottles of soda, it has a mass of 11.3 kg. When the ice box is packed with 20 identical packets of milo, it has a mass of 9.3 kg. A bottle of soda weighs 480 g more than a packet of milo. What is the mass of the empty ice box in kg?
1000 g = 1 kg
480 g = 480 ÷ 1000 = 0.48 kg

Mass of 1 packet of milo = 1 P
Mass of 1 bottle of soda = 1 P + 0.48

Mass of 20 packets of milo = 20 P
Mass of 10 bottles of soda = 10(1 P + 0.48) = 10 P + 4.8 

Ice Box + 10 P = 11.3 - 4.8 = 6.5
Ice Box + 10 P = 6.5 --- (1)

Ice Box + 20 P = 9.3 --- (2)

(2) - (1)
20 P - 10 P = 9.3 - 6.5 
10 P = 2.8

1 P = 2.8 ÷ 10 = 0.28

10 P = 10 x 0.28 = 2.8

Mass of the empty ice box
= 6.5 - 2.8
= 3.7 kg

Answer(s): 3.7 kg