When an ice box is packed with 10 identical bottles of coke, it has a mass of 8.4 kg. When the ice box is packed with 15 identical packets of orange juice, it has a mass of 3.45 kg. A bottle of coke weighs 560 g more than a packet of orange juice. What is the mass of the empty ice box in kg?
1000 g = 1 kg
560 g = 560 ÷ 1000 = 0.56 kg

Mass of 1 packet of orange juice = 1 P
Mass of 1 bottle of coke = 1 P + 0.56

Mass of 15 packets of orange juice = 15 P
Mass of 10 bottles of coke = 10(1 P + 0.56) = 10 P + 5.6 

Ice Box + 10 P = 8.4 - 5.6 = 2.8
Ice Box + 10 P = 2.8 --- (1)

Ice Box + 15 P = 3.45 --- (2)

(2) - (1)
15 P - 10 P = 3.45 - 2.8 
5 P = 0.65

1 P = 0.65 ÷ 5 = 0.13

10 P = 10 x 0.13 = 1.3

Mass of the empty ice box
= 2.8 - 1.3
= 1.5 kg

Answer(s): 1.5 kg