A container filled with 9 mangoes has a mass of 9.65 kg. The same container when filled with 10 passion fruits has a mass of 1.7 kg. The mass of 1 mango is seven times the mass of 1 passion fruit. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

9.65 kg = 9650 g
1.7 kg = 1700 g

1 passion fruit = 1 u
10 passion fruits = 10 x 1 u = 10 u

1 container + 10 passion fruits = 1700
1 container + 10 u = 1700 --- (1)

1 mango = 7 u
9 mangoes = 9 x 7 u = 63 u

1 container + 9 mangoes = 9650
1 container + 63 u = 9650 --- (2)

(2) - (1)
63 u - 10 u = 9650 - 1700
53 u = 7950

1 u = 7950 ÷ 53 = 150

10 u = 10 x 150 = 1500

From (1):
1 container + 10 u = 1700
1 container + 1500 = 1700
 
1 container = 1700 - 1500 = 200

Mass of 1 container = 200 g

Answer(s): 200 g