A container filled with 8 king melons has a mass of 13 kg. The same container when filled with 10 chikoos has a mass of 2.2 kg. The mass of 1 king melon is eight times the mass of 1 chikoo. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

13 kg = 13000 g
2.2 kg = 2200 g

1 chikoo = 1 u
10 chikoos = 10 x 1 u = 10 u

1 container + 10 chikoos = 2200
1 container + 10 u = 2200 --- (1)

1 king melon = 8 u
8 king melons = 8 x 8 u = 64 u

1 container + 8 king melons = 13000
1 container + 64 u = 13000 --- (2)

(2) - (1)
64 u - 10 u = 13000 - 2200
54 u = 10800

1 u = 10800 ÷ 54 = 200

10 u = 10 x 200 = 2000

From (1):
1 container + 10 u = 2200
1 container + 2000 = 2200
 
1 container = 2200 - 2000 = 200

Mass of 1 container = 200 g

Answer(s): 200 g