Im having trouble briefing this case. What is the law and rationale?

Fact Scenario Bob Corona wanted to own a bar since the day he stepped in one. He opened Bob's Beer Bash 5 years ago and found out how hard he had to work to keep it in operation. Bob decided that he did not want to spend his retirement dealing with all the stressful responsibilities of ownership. After his 5 years of ownership, he sold his business, Bob's Beer Bash, to Joe Guinness. Joe agreed to allow Bob to continue to manage the bar. Joe did not change the name of the bar Joe authorized Bob to order certain items for the business such as beer, juice, soda and napkins. Bob would order these items once a month to keep the bar stocked. Bob would place these orders by phone to World Imports, Inc. When the ordered items were delivered, Bob would sign the World Imports Inc, delivery form. Joe would then pay for the items in a timely and reasonable manner. After a year of ordering these items from World Imports, Inc., Bob decided on his own that the Bar menu needed some 'zip'! So, in addition to these authorized items for 4 months Bob ordered expensive French wine, expensive cigars, and Russian caviar from World Imports, Inc. These new additions to the menu brought in a different class of customer that increased the bar's revenue, as well as Bob's tip jar These items were shipped from World Imports Inc each month to Bob's Beer Bash, but the business was not able to pay for them. For the first 2 months, Joe paid for all of the purchases, Type here to search

After a year of ordering these items from World Imports, Inc., Bob decided, on his own, that the Bar menu needed some 'zip'! So, in addition to these authorized items, for 4 months Bob ordered expensive French wine, expensive cigars, and Russian caviar from World Imports, Inc. These new additions to the menu brought in a different class of customer that increased the bar's revenue, as well as Bob's tip jar. These items were shipped from World Imports, Inc. each month to Bob's Beer Bash, but the business was not able to pay for them. For the first 2 months, Joe paid for all of the purchases, primarily because the caviar had been selling so well at the bar. For the next 2 months Joe paid only for the items that he had authorized Bob to order. World Imports, Inc. sued Bob's Beer Bash World Imports, Inc. claimed that Bob's Beer Bash should have to pay for all the purchases made. Bob's Beer Bash claimed that it should not be responsible for any of the purchases it had not authorized Bob to make