1) The waters prevailed 15 cubits above all the mountains of the earth. (Gen 7:20)
2) The waters prevailed over the earth 150 days. For the ark to later come to rest on the mountains of Ararat, the waters had to recede 15 cubits in 150 days, 1 cubit every 10 days. (Gen 7:24)
3) The hangings for the gate of the court in the tabernacle were 15 cubits on both sides. (Exo 27:14-15)
4) The feast of unleavened bread begins on the 15th day of the first month. (Lev 23:6)
5) Israel left Rameses on the 15th day of the first month. (Num 33:3)
6) God added 15 years to the life of Hezekiah. (II Kings 20:6)
7) Esther and Mordecai established the feasts of Purim on the 14th & 15th day of Adar. (Esther 9:18)
8) Luke 3:1 begins the story of John the baptist by stating that he began his ministry in the 15th year of Tiberius Caesar.
9) Bethany was 15 stadia from Jerusalem. (John 11:18)
10) After sounding 15 fathoms, the sailors on Paul's ship started praying for day light. (Acts 27:28)
11) Paul stayed 15 days with Peter. (Gal 1:18)
So what is the Spiritual meaning of the number FIFTEEN as it occurs and is used in Scripture? And what are the rules used in determining numeric symbolisms?