Linux permissions and ACLs quiz

Ten questions across the whole chapter. Each answer explains why. Aim for eight before moving on to chapter 8.

A file has mode 640, owner maria, group project. Which user gets read access?
What is the mode after chmod u=rwx,g=rx,o= file?
Which command reports permissions in octal?
What does capital X do in chmod -R g+rX?
umask is 027. A user creates a directory. What mode does it get?
Which setup gives a team a shared directory where new files belong to the team group?
What does the sticky bit on /tmp prevent?
Which file would setuid root be dangerous on?
A named ACL entry is rw- but the mask is r--. What is the effective access?
Which command shows who can reach a file by checking each directory on the way?