Can someone please tell me why we don't account for opening and closing payable in this question? Thank you

Because Accounts Payable didn’t change.

The adjustments to Net Income to get to CFO involve, in addition to other non-cash items, changes in working capital accounts, of which Accounts Payable is one. The change, however, is zero. If you want to add (or subtract) zero in your calculation, you’re welcome to do so, but it won’t change the result.

omg I mistakenly looked at account receivables ending and thought it was account payable. I’m such an idiot lol. Thanks friend!

My pleasure.