A container filled with 11 king melons has a mass of 10.17 kg. The same container when filled with 3 apples has a mass of 0.72 kg. The mass of 1 king melon is six times the mass of 1 apple. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

10.17 kg = 10170 g
0.72 kg = 720 g

1 apple = 1 u
3 apples = 3 x 1 u = 3 u

1 container + 3 apples = 720
1 container + 3 u = 720 --- (1)

1 king melon = 6 u
11 king melons = 11 x 6 u = 66 u

1 container + 11 king melons = 10170
1 container + 66 u = 10170 --- (2)

(2) - (1)
66 u - 3 u = 10170 - 720
63 u = 9450

1 u = 9450 ÷ 63 = 150

3 u = 3 x 150 = 450

From (1):
1 container + 3 u = 720
1 container + 450 = 720
 
1 container = 720 - 450 = 270

Mass of 1 container = 270 g

Answer(s): 270 g