It’s 18 to 9 (Official clock system).

08:42

It’s 18 to 9.

Correct answer

08:41

It’s 19 to 9.

Error: 1 minute earlier

07:50

It’s 10 to 8.

Error: read minutes starting from hour markings and adding minutes

08:40

It’s 20 to 9.

Error: confuse hour and minute hands