Determine the mass of iron contained in 1 ton of cast iron with 8% impurities.

Given:
m (cast iron) = 1 t = 1,000,000 g
ω approx. = 8%

To find:
m (Fe) -?

Decision:
1) Calculate the mass fraction of iron in cast iron:
ω (Fe) = 100% – ω approx. = 100% – 8% = 92%;
2) Calculate the mass of iron in cast iron:
m (Fe) = ω (Fe) * m (cast iron) / 100% = 92% * 1,000,000 / 100% = 920,000 g = 920 kg.

Answer: The mass of iron in cast iron is 920,000 g (920 kg).