A container filled with 12 jackfruits has a mass of 10.32 kg. The same container when filled with 5 kiwis has a mass of 0.84 kg. The mass of 1 jackfruit is seven times the mass of 1 kiwi. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

10.32 kg = 10320 g
0.84 kg = 840 g

1 kiwi = 1 u
5 kiwis = 5 x 1 u = 5 u

1 container + 5 kiwis = 840
1 container + 5 u = 840 --- (1)

1 jackfruit = 7 u
12 jackfruits = 12 x 7 u = 84 u

1 container + 12 jackfruits = 10320
1 container + 84 u = 10320 --- (2)

(2) - (1)
84 u - 5 u = 10320 - 840
79 u = 9480

1 u = 9480 ÷ 79 = 120

5 u = 5 x 120 = 600

From (1):
1 container + 5 u = 840
1 container + 600 = 840
 
1 container = 840 - 600 = 240

Mass of 1 container = 240 g

Answer(s): 240 g