$1.$ Smith Construction is building a warehouse for Raymond. The construction firm routinely leaves certain construction equipment at the building site overnight and on weekends. Late one night, Fred, age $10,$ began playing on some of Smith$$s construction equipment. Fred accidentally released the brakes of a tractor on which he was playing, and the tractor rolled down a hill and smashed into the building under construction. Fred was severely injured in the accident. Fred$$s parents sued both Smith Construction and Raymond for the injury.

a$.$ Based on the elements of negligence, describe the requirements that must be met for Smith Construction to be held liable for negligence.

b$.$ Describe the various classes of persons that are recognized by the law with respect to entering the property of another. In which class of persons would Fred belong?

c$.$ What other legal doctrine is applicable in this case because of Fred$$s age? Explain your answer.

$4.$ Matthew was involved in an auto accident. He was judged to be $40$ percent at fault in the accident, and the other party was judged to be $60$ percent at fault. Matthew$$s actual damages were $$50,000.$ Under a pure comparative negligence law, how much, if anything, will Matthew receive for his injury?