When an ice box is packed with 10 identical bottles of coke, it has a mass of 7.6 kg. When the ice box is packed with 15 identical packets of orange juice, it has a mass of 4.15 kg. A bottle of coke weighs 410 g more than a packet of orange juice. What is the mass of the empty ice box in kg?
1000 g = 1 kg
410 g = 410 ÷ 1000 = 0.41 kg

Mass of 1 packet of orange juice = 1 P
Mass of 1 bottle of coke = 1 P + 0.41

Mass of 15 packets of orange juice = 15 P
Mass of 10 bottles of coke = 10(1 P + 0.41) = 10 P + 4.1 

Ice Box + 10 P = 7.6 - 4.1 = 3.5
Ice Box + 10 P = 3.5 --- (1)

Ice Box + 15 P = 4.15 --- (2)

(2) - (1)
15 P - 10 P = 4.15 - 3.5 
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
= 3.5 - 1.3
= 2.2 kg

Answer(s): 2.2 kg