TSA 2015 · Question 6 · Logic
SaveWilliam wants to cook roast beef and potatoes for himself and four friends. From his cookbook he gets the following information: [image of table 1] After removing from the oven, the meat should be allowed to stand for 10 minutes. [image of table 2] William buys a joint of the correct weight and decides to cook it medium rare in a hot oven.

How long after putting the beef in the oven should he put in the potatoes, so that both will be ready to serve at the same time?