married filing jointly, partner's a business owner, can I deduct the cost of buying a used car?

We are a married couple based in California

We have decided to buy a used car for my partner's business use.

We typically file jointly. 

Question is, if the used car cost $20,000, and my partner only brings in $10,000 doing real state, and I bring in $100,000 as a salary person (W2 based) at end of 2021, can I deduct 100% of the car cost, or only up-to $10,000?

 

 

Thanks,