Answer: a) Labor force participation rate = 72.46%, b) Unemployment rate = 1.8%.
Explanation:
Since we have given that
Number of people who have at least a bachelor's degree = 71.9 millions
Number of people who were employed = 52.1 millions
Number of people who were unemployed = 1.3 millions
So, Labor- force participation rate would be

Unemployment rate for this group would be

Hence, a) 72.46%, b) 1.8%.