The owner of a boat took two friends out on a lake near his home. one of his friends was driving the boat when it struck a partially submerged rock that the owner of the boat had forgotten to tell him about. the owner of the boat and the other passenger were injured; the driver of the boat was not hurt.

in a jurisdiction that applies joint and several liability with comparative contribution, the passenger brought suit against both the boat owner and the driver, and the boat owner also sued the driver. the jury determined that the boat owner was 55% at fault and suffered $10,000 in damages, the driver of the boat was 45% at fault, and the injured passenger suffered $100,000 in damages. after entry of judgment, the boat owner paid the passenger her total damages of $100,000, while the driver of the boat has paid nothing.

how much, if anything, can the boat owner recover from the driver?