DOUBLE ENTRY BOOKKEPPING

Hello professor,

i dont get this question.

The transaction of Alis new business in its first week were as follows:

1. Commenced business with the intorudcion of 1000$ cash
2. Paid 350 $ rent
3. purchaed a delivery van for 400$ cash

So i am confuesd with number 3.
it says: Assets= Equity +Liability

650 (400-400)= 650+0
Why is like this can you explain me, because for me this would be, cash decreased for 400, and also payables to suppliers. i dont get number three.

Thank you