Hi.....i'm stuck on the following question;

Show that no infinite soluble group has a composition series.

The hint for the question was to try by contradiction.

So i tried the following;

Suppose G is an infinite soluble group with a composition series.

G is soluble so all composition factors are cyclic and of prime order.

I think there will be a contradiction because G is infinite...but i just don't know

Thanks for your help