Answer: The US has the longest average workweek among the top 10 countries
Step-by-step explanation:
The reason why the United State ranks fifth for productivity when considering the GDP per hour worked is due to the fact that the country has the longest average workweek among the top 10 countries.
Due to the fact that people in the United States spend much of their time at work, this has resulted into a scenario which led to the reduction in their productivity despite having highest GDP as the workers may get tired due to the work stress and this has a negative effect on the workers.