A container filled with 10 honeydews has a mass of 12.15 kg. The same container when filled with 5 persimmons has a mass of 0.9 kg. The mass of 1 honeydew is eight times the mass of 1 persimmon. Find the mass of the container when it is empty. Express the answer in g.
1 kg = 1000 g

12.15 kg = 12150 g
0.9 kg = 900 g

1 persimmon = 1 u
5 persimmons = 5 x 1 u = 5 u

1 container + 5 persimmons = 900
1 container + 5 u = 900 --- (1)

1 honeydew = 8 u
10 honeydews = 10 x 8 u = 80 u

1 container + 10 honeydews = 12150
1 container + 80 u = 12150 --- (2)

(2) - (1)
80 u - 5 u = 12150 - 900
75 u = 11250

1 u = 11250 ÷ 75 = 150

5 u = 5 x 150 = 750

From (1):
1 container + 5 u = 900
1 container + 750 = 900
 
1 container = 900 - 750 = 150

Mass of 1 container = 150 g

Answer(s): 150 g