Suppose that some country had an adult population of about 50 million, a labor-force participation rate of 60 percent, and an unemployment rate of 5 percent. how many people were unemployed?

60% of 50 mill ... 0.6 (50 mill) = 30 mill ... this is the labor force participation

unemployment rate of 5% ... 0.05 (30 mill) = 1.5 mill

1.5 million were unemployed <==

* * if the unemployment rate is 5%, that means 5% of the labor force, not the entire adult population because some of the adult population might be too old or disabled and cant participate in the labor force. The labor force is people that are able to work.