A 27.0 kg block resting on a horizontal table is connected to an empty 3.50 kg bucket that is hanging over the edge of the table by cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.644. Sand is gradually added to the bucket until the block and the bucket just begin to move. a) What is the total mass of the sand in kilograms added to the bucket? (Enter a number with one decimal place and no units in the space below.)