It’s 18 to 4 (Official clock system).

03:42

It’s 18 to 4.

Correct answer

03:43

It’s 17 to 4.

Error: 1 minute later

02:50

It’s 10 to 3.

Error: read minutes starting from hour markings and adding minutes

08:15

It’s a quarter past 8.

Error: confuse hour and minute hands