24? (subtract 2^3, then 2^2, then 2^1...)
or 29 (difference of differences = +6)
or...
If it's a mathematical sequence we would need more terms as ther eare so many answers. But sometimes these questions have a non-mathematical solution- eg numbers on players' shirts who scored ina cup final- or that sort of thing
There is a question on Quora.com which asks what is the next number in this sequence and why? 35 29 27 17 25 22 21 together with an explanation as to how the next number will be 16.
If the answer for petesgrayz is a natural progression the answer is 21 but 3 numbers is not much to go on.
The numbers are hex base numbers for red green and blue. The next colour seems to be yellow but conversion (FFFF00)is not my strong point. Google the numbers as 352725 and this should lead you to the table of colours and their values in various mathematical forms. Good luck this has been a real poser.
I can also make a case for 25:
Starting with 35:
then
35 - (3² - 1) = 27
27 - (3¹ -1) = 25
25 - (3⁰- 1) = 25
There must be lots of other equally valid solutions. We either need more terms or a steer as to what type of quiz it is- is it likely to be maths sequence or something like the number of goals Harry Kane scored in successive seasons or the number of months successive PMs served for etc
Thanks Pentland- yours wasn't there when I started thinking and typing mine. It probably is something like that rather than a mathematical number sequence
When Douglas Adams wrote The Hitchhiker's Guide to the Galaxy, he added a central joke which has become more famous over the years than the novel itself: "The answer to the ultimate question of life, the universe and everything is 42."
Hopefully pete can come back and clarify the question and quiz but as he hasn't joined in on his own questions for a few years now (maybe the answer button is greyed out- some report it sometimes happens) I am not particularly optimistic