A container filled with 12 honeydews has a mass of 12.2 kg. The same container when filled with 9 mangoes has a mass of 2 kg. The mass of 1 honeydew is five times the mass of 1 mango. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

12.2 kg = 12200 g
2 kg = 2000 g

1 mango = 1 u
9 mangoes = 9 x 1 u = 9 u

1 container + 9 mangoes = 2000
1 container + 9 u = 2000 --- (1)

1 honeydew = 5 u
12 honeydews = 12 x 5 u = 60 u

1 container + 12 honeydews = 12200
1 container + 60 u = 12200 --- (2)

(2) - (1)
60 u - 9 u = 12200 - 2000
51 u = 10200

1 u = 10200 ÷ 51 = 200

9 u = 9 x 200 = 1800

From (1):
1 container + 9 u = 2000
1 container + 1800 = 2000
 
1 container = 2000 - 1800 = 200

Mass of 1 container = 200 g

Answer(s): 200 g