6. As part of his summer job at a reetaurant, George learned to eook a large pot of soup late at night, just before closing time, so that there would be plenty of soup to feed customers the next day. He aleo found out that, while refrigeration was essential to preserve the soup overnight, the soup was too hot to be put direcetly into the fridge when it was ready. (The soup had just beiled at 100 degrees Celsius, and the fridge was not powerfal enough to aecomodate a big pot of soup if it was any warmer than 20 degrees Celsius). George disoovered that by cooling the pot in a sink full of cold water, Ckept running so that ita temperature was roughly constant at 5 degrees Celsius) and stirring oocasionally, he could bring that temperature of the soup to 60 degrees Celsius in ten minutes. How long before closing time should the soup be ready so that George could put it in the fridge and leave on time