A container filled with 13 jackfruits has a mass of 13.86 kg. The same container when filled with 10 kiwis has a mass of 1.71 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

13.86 kg = 13860 g
1.71 kg = 1710 g

1 kiwi = 1 u
10 kiwis = 10 x 1 u = 10 u

1 container + 10 kiwis = 1710
1 container + 10 u = 1710 --- (1)

1 jackfruit = 7 u
13 jackfruits = 13 x 7 u = 91 u

1 container + 13 jackfruits = 13860
1 container + 91 u = 13860 --- (2)

(2) - (1)
91 u - 10 u = 13860 - 1710
81 u = 12150

1 u = 12150 ÷ 81 = 150

10 u = 10 x 150 = 1500

From (1):
1 container + 10 u = 1710
1 container + 1500 = 1710
 
1 container = 1710 - 1500 = 210

Mass of 1 container = 210 g

Answer(s): 210 g