A container filled with 15 king melons has a mass of 9.17 kg. The same container when filled with 10 starfruits has a mass of 1.67 kg. The mass of 1 king melon is four times the mass of 1 starfruit. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

9.17 kg = 9170 g
1.67 kg = 1670 g

1 starfruit = 1 u
10 starfruits = 10 x 1 u = 10 u

1 container + 10 starfruits = 1670
1 container + 10 u = 1670 --- (1)

1 king melon = 4 u
15 king melons = 15 x 4 u = 60 u

1 container + 15 king melons = 9170
1 container + 60 u = 9170 --- (2)

(2) - (1)
60 u - 10 u = 9170 - 1670
50 u = 7500

1 u = 7500 ÷ 50 = 150

10 u = 10 x 150 = 1500

From (1):
1 container + 10 u = 1670
1 container + 1500 = 1670
 
1 container = 1670 - 1500 = 170

Mass of 1 container = 170 g

Answer(s): 170 g