> s = "and the answer is: "
> list.each {|item| s << item }
> puts s
> testltlt.rb:4:in `<<': failed to convert Float into String (TypeError)
> Why?

I think you can only concatenate with another string ( so you could use
<< item.to_s instead of just << item ) or with an integer, in which case
the character corresponding to the integer taken as an ascii code, is
concatenated.

Barry