If you are cooking a brisket in the oven, it typically takes around 1 hour and 15 minutes per pound at 250°F (120°C). For example, a 6-pound brisket would take around 7.5 hours to cook. If you are cooking a brisket on a smoker or grill, the cooking time can vary depending on the temperature of the smoker or grill and the size of the brisket. As a general rule, it can take around 1 to 1.5 hours per pound at a temperature of around 225°F (110°C) to 250°F (120°C). However, it's important to use a meat thermometer to ensure that the internal temperature of the brisket reaches at least 190°F (88°C) to 205°F (96°C) before removing it from the smoker or grill. Remember to let the brisket rest for at least 30 minutes before slicing and serving to allow the juices to redistribute throughout the meat.