Answer:
I think the answer is 23
Explanation:
Because the pattern is # - 2 - 1 x 2 + 1
That is because 10 is the starting number and 10 - 2 is 8 and 8 - 1 is 7 and 7 x 2 is 14 and 14 + 1 is 15 and then it starts the process all over again with 15 - 2 is 13 and 13 - 1 is 12 and 12 x 2 is 24 and 24 + 1 is 25. And so 25 would be the end of the second round of the pattern. So it would start again with 25 - 2 is 23... and so on and so forth.
Hope this helps!!