your answer is correct, but incomplete. I think you are supposed to tell for 5 of the files, why they need to be setuid root. For example, passwd is setuid root so users can change their own password, ping is setuid root because it needs to create raw sockets and so on.
I also think your command will not have the effect you want (in case you intend to pipe the files to ls). You are probably looking for something like this
for file in `find / -perm +4000`;do ls -l $file ;done
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