Iron ore contains iron and impurities in a ratio of 7: 2. Find the number of tons of iron that will be obtained

Iron ore contains iron and impurities in a ratio of 7: 2. Find the number of tons of iron that will be obtained from 819 tons of ore?

We will solve this task in steps and explain each of them in detail.
1) 7 + 2 = 9 parts – is iron ore, since it contains iron and impurities in a ratio of 7: 2;
2) 819: 9 = 91 tons – falls on one part, since all iron ore is 9 parts weighing 819 tons;
3) 7 * 91 = 637 tons of iron – contained in iron ore weighing 819 tons, since iron is 7 parts out of 11.
Answer: 637 tons of iron.