This is a Strengthen with Necessary Premise question.
The stimulus presents an argument, the conclusion of which is "For the same reason jurisdictions should also require helmets for horseback riders, since horseback-riding accidents are even more likely to cause serious head injury than motorcycle accidents are."
What is odd about this conclusion is that it appears to come out of nowhere - the entirety of the stimulus before this last sentence is about motorcycle accidents and head injuries resulting from those accidents, and yet suddenly we are talking about horseback riding accidents.
The premises offered in support of the subsidiary conclusion that other jurisdictions should enact motorcycle helmet laws have to do with the cost reductions such laws will provide - which, in turn, are a result of the cost to taxpayers for medical care when nonhelmeted motorcycle-accident victims are injured.
So for us to strengthen a conclusion about horseback riding helmet laws based on premises about cost savings for motorcycle helmet laws, we need to establish that taxpayers suffer costs when nonhelmeted horseback riders are injured, too. That's answer choice (A).
Answer choice (D) is not necessary in this context - it's about fatalities, rather than injuries. What we care about is the cost of medical care for those who are injured - not those who are killed.
Hope this helps. Please let us know if you have any additional questions.
ahlamJune 5, 2019
Hi, I am also having trouble understanding why c is not the correct answer. If the medical costs associated with treating head injuries are higher than those for other types of injuries, then wouldn't that mean that it leads increase costs to taxpayers and helmet laws would reduce these injuries and therefore the costs? Thanks!
RaviJune 7, 2019
@ahlam,
Happy to help. Let's take a look at (C).
(C) says, "The medical costs associated with treating head injuries are higher than those for other types of injury."
(C)'s negation is the medical costs associated with treating head injuries are no higher than those for other types of injury.
The problem with (C) is that we don't have to assume that head injuries are the most expensive ones to treat because even if it's the case that there are other types of injuries that are more expensive to treat than head injuries, it's possible that we could still save money by reducing the rate of head injuries. Thus, (C) isn't a necessary premise for the argument. We see that with (C)'s negation, as it does not wreck the argument. If (C)'s negation had wrecked the argument, then we would know that it's essential for the argument.
Hope this helps. Let us know if you have any other questions!
