Which compromises solved the biggest challenges to ratifying the Constitution?

The two major compromises in the Constitutional Convention was the Virginia Plan and the 3/5 compromise. The Virginia Plan called called for a bicameral congress where one house would be represented per population and the other house would be equal representation for each state. The 3/5 compromise said that slaves counted for 3/5 of a person (used as population to determine number of seats in the House of Representatives).