solution: It is a geometric progression. and most appropriate relationship is x×
.
Step-by-step explanation:
let the number of competitors in first round be x.
number of competitors in 2nd round will be
.
number of competitors in 3rd round will be
=

similarly, number of competitors in next round will be
=

and so on.
so number of competitors in various rounds are forming a sequence
i.e.,

now ratio of second and first term =
=

similarly, ratio of third and fourth term =
=

and so on.
so, it is forming a geometric progression .
where the first term i.e.,a = x
and common ratio i.e., r =
.
so here, most appropriate relationship is

i.e., x×
.