A and B are partners. The firm runs a business of making and selling DVDs. They have a partnership agreement that, no one shall enter into a contract amounting to more than 40k without the consent of other partners.

So on 1st April, A enters a contract with X without B's consent to buy a second-hand van worth 80k for the purpose of transporting their goods.

So, does B and the firm liable for the transaction made by A? how should I advise B?

What are the case and law related to the scenario above?