At 81, which man was the oldest delegate at the 1787 Constitutional Convention?

In 1776, George Washington and his troops crossed which river to attack the Hessians? Which 1781 document declared that "each state retains its sovereignty, freedom and independence"? In which 1783 treaty did "His Britannic Majesty" acknowledge the United States to be "free, sovereign and independent"? Which 1783 treaty, negotiated by John Adams, Benjamin Franklin and John Jay, ended the Revolutionary War? Which 1787 law governing the area north of the Ohio River became a model for territories entering the Union? In 1787, which state became the first to ratify the Constitution? Who served as U.S. vice president from 1789 to 1797? Which document went into effect in 1789?