The forces operating on the wood block are balanced since it is at rest. This implies that the force applied on the block by the table must be equal to and opposing to the 15 N weight of the block. As a result, the table is pushing on the block with a force of 15 N, but in an upward direction. The block may stay at rest on the table because the upward force from the table counteracts the downward force of gravity acting on it.
Explained: This is due to Newton's third law of motion, which states that every action has a corresponding and opposing response. As a result, the force applied by the table to the block should be equivalent in size but applied in the opposite direction to that applied by the block to the table.