It’s 21 past 3 (Alternative clock system).

15:21

It’s 21 past 3.

Correct answer

15:22

It’s 22 past 3.

Error: 1 minute later

15:05

It’s 5 past 3.

Error: read minutes starting from hour markings and adding minutes

16:15

It’s a quarter past 4.

Error: confuse hour and minute hands