11
10 because it's an even number !
Every other number is 1 3 5 7 9 11. The second set of numbers are 10 9 8 7 6. So to continue the series it would be 5 13 4 15 3 17 2 19 1 21.
the answer is 1
7
What would be the next number in this series 15 12 13 10 11 8?
11 because 4+1=5 3+5=8 2+8=10 1+10=11 0+11=11
10 4 3 11 15 9 8 16 20....
11
13
11
11