Find the next number in the following sequences:
1) 13, 13, 26, 39, 52, __________
2) 3, 4, 6, 9, 13, _____________
3) 800, 400,200,100, 50 _____________
4) 16, 32, 48, 64, 80, _____________
5) 35, 17, 40, 22, 45, 27, ___________
6) 16, 18, 23, 25, 30, 32, ____________
7) 96, 48, 24, 12, 6, ___________
8) 1.75, 2.5, 3.25, 4, 4.75, ___________
9) 1, 2, 3, 6, 5, 10, __________
10) 2, 10, 40, 120, 240, _________
11) 72, 72, 36, 12, __________
