Answer:
66.7% is the answer.
Explanation:
A country has 50 million people, 30 million of whom are adults.
Of the adults, 5 million are not interested in working.
5 million are interested in working but have given up looking for work.
5 million are still looking for work.
Of those who do have jobs, 5 million are working part time but would like to work full time, and the remaining 10 million are working full time.
Total labor force = Employed people + Unemployed people
=> 15 million+ 5 million = 20 million
The labor force participation rate is

= 66.66% ≈ 66.7%.