The War of Jenkins' Ear  broke out in 1739 between Spain and Great Britain, but was confined to the Caribbean Sea and conflict between Spanish Florida and the neighboring British Province of Georgia. The War of the Austrian Succession, nominally a struggle over the legitimacy of the accession of Maria Theresa to the Austrian throne, began in 1740, but at first did not involve either Britain or Spain militarily. Britain was drawn diplomatically into that conflict in 1742 as an ally of Austria and an opponent of France and Prussia, but open hostilities between them did not take place until 1743 at Dettingen, and war was only formally declared between Britain and France in March 1744. Massachusetts did not declare war until June 2.
How many years after the start of The War of the Austrian Succession was war formally declared between Britain and France?
4