When an ice box is packed with 25 identical bottles of soda, it has a mass of 17.5 kg. When the ice box is packed with 35 identical packets of green tea, it has a mass of 8.45 kg. A bottle of soda weighs 430 g more than a packet of green tea. What is the mass of the empty ice box in kg?
1000 g = 1 kg
430 g = 430 ÷ 1000 = 0.43 kg

Mass of 1 packet of green tea = 1 P
Mass of 1 bottle of soda = 1 P + 0.43

Mass of 35 packets of green tea = 35 P
Mass of 25 bottles of soda = 25(1 P + 0.43) = 25 P + 10.75 

Ice Box + 25 P = 17.5 - 10.75 = 6.75
Ice Box + 25 P = 6.75 --- (1)

Ice Box + 35 P = 8.45 --- (2)

(2) - (1)
35 P - 25 P = 8.45 - 6.75 
10 P = 1.7

1 P = 1.7 ÷ 10 = 0.17

25 P = 25 x 0.17 = 4.25

Mass of the empty ice box
= 6.75 - 4.25
= 2.5 kg

Answer(s): 2.5 kg