It’s 18 to 4 (Alternative clock system).

03:42

It’s 18 to 4.

Correct answer

03:41

It’s 19 to 4.

Error: 1 minute earlier

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