It’s 24 to 9 (Official clock system).

20:36

It’s 24 to 9.

Correct answer

20:35

It’s 25 to 9.

Error: 1 minute earlier

19:52

It’s 8 to 8.

Error: read minutes starting from hour markings and adding minutes

19:40

It’s 20 to 8.

Error: confuse hour and minute hands