To determine which country's total war spending was the highest at the end of World War I, we analyze the given spending amounts for each country:
- United Kingdom: \[tex]$39.9 billion
- France: \$[/tex]24.3 billion
- Russia: \[tex]$22.6 billion
- Germany: \$[/tex]37.7 billion
- United States: \[tex]$22.6 billion
By comparing these amounts, we can see:
- The United Kingdom spent \$[/tex]39.9 billion.
- France spent \[tex]$24.3 billion, which is less than what the United Kingdom spent.
- Russia spent \$[/tex]22.6 billion, which is also less than the spending by the United Kingdom.
- Germany spent \[tex]$37.7 billion, which is still less than the United Kingdom's spending.
- The United States spent \$[/tex]22.6 billion, again less than what the United Kingdom spent.
Since the United Kingdom's spending of \$39.9 billion is more than the spending of any other listed country, we can conclude that the United Kingdom had the highest total war spending at the end of World War I.
Therefore, the answer is:
the United Kingdom.
