It’s 18 to 8 (Official clock system).

07:42

It’s 18 to 8.

Correct answer

07:43

It’s 17 to 8.

Error: 1 minute later

06:50

It’s 10 to 7.

Error: read minutes starting from hour markings and adding minutes

08:35

It’s 25 to 9.

Error: confuse hour and minute hands