5. In the first quarter of 2012, the total export value of a certain province was 8.07 billion US dollars, which is 1.5 times the import value plus an additional 1.11 billion US dollars. The total import value of the province in this quarter was $\qquad$ billion US dollars.
【Analysis】The total import value is $(80.7-11.1) \div 1.5=46.4$ billion US dollars.