#20, 10, 2.5# ?
It is not clear what this question is asking.
What is the next number in the sequence
#2.5 / 6 = 0.41bar(6)#
#2.5 / 8 = 0.3125#
Since this does not fall into the category of any standard sequence, we could justify all kinds of continuations of the sequence.
What number is missing in the geometric sequence
Note that the sequence:
#20, 10, color(red)(5), 2.5#
would be a geometric sequence, with each term being half of the preceding one.
What is the rule and next term of the sequence
Note this assumes that
If so, then this looks like a geometric sequence with initial term
The formula for a general term would be:
#a_n = 20*(1/2)^(n-1)#
and the next term of the sequence would be:
#2.5*(1/2) = 1.25#