Kyle, Brian and Pam are all partners in a general partnership that is engaged in the business of event planning. Kyle contributed 45% of the capital, Brian contributed 40% of the capital, and Pam contributed 15% of the capital of the partnership. Without the other partners' knowledge, Pam purchased new marketing materials. The bill has arrived for the marketing materials. Who is liable to pay for the materials? Why? Discuss fully and identify the name of any legal principle that governs your answer.