Firm XYZ operates in a perfectly competitive market and can sell as much of its product as it wants at the market price (without affecting the market price). XYZ produces "doodads." Each doodad sells for $25. (These are very nice doodads). When XYZ hired its first worker, output increased from zero to 42 units. When the second worker was hired, output increased to 75. What is the VMP of the second worker?