It’s 20 past 10 (Official clock system).

10:20

It’s 20 past 10.

Correct answer

09:40

It’s 20 to 10.

Error: mirror minute hand about the vertical axis

10:04

It’s 4 past 10.

Error: read minutes as hours with ‘past’ or ‘to’

04:50

It’s 10 to 5.

Error: confuse hour and minute hands