calculate the mean deviation of the marks scored by a class of 40 student in test. mark=48,53,58,63,68,73,78,84,88. and number of student = 2,2,5,6,7,11,4,2,1​

A10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. which one has the greater buoyant force on it? explain. b - the aluminum a) both have the same buoyant force. b) the aluminum c) the lead d) it cannot be determined without knowing their volumes.