A reason Larson cannot do the assignment is that she has an unavoidable scheduling conflict. On the other hand, a rea...

Mehran on September 26, 2014

Thanks for your message. Let's break down this argument.

Premise: Larson cannot do assignment because she has an unavoidable scheduling conflict.

Premise: Franks cannot do the assignment because he does not quite have the assertiveness the task requires.

Conclusion: Task must be assigned to Parker, the only supervisor in the shipping department other than Larson and Franks.

This is clearly a flawed argument. Why must the task be assigned to Parker if Larson and Franks cannot do it? We have nothing that states the only people who can complete this assignment are Larson, Franks and Parker.

That is the missing assumption here, i.e. that Larson, Franks and Parker are the only people who can complete this assignment.

Answer choice (B) states exactly that, "The task cannot be assigned to anyone other than a supervisor in the shipping department (i.e. Larson, Franks and Parker)."

This is a Strengthen with Necessary Premise question so while (B) clearly strengthens the argument, let's make sure it is also required for the argument.

When you negate (B), it becomes, "The task can be assigned to someone other than a supervisor in the shipping department." This clearly destroys the argument so (B) is the correct answer.

Hope this helps! Please let us know if you have any other questions.

ariella on February 8, 2017

Why is C incorrect?

jayw on January 31, 2019

Why can't the answer be E ?

Ravi on February 1, 2019

@ariella and @jayw,

Great questions. As Mehran noted, this is a strengthen with a
necessary premise question, so the answer we choose is required in
order for the argument to stand a chance, whereas the incorrect
answers are not required for the argument to hold.

In order to see whether or not an answer choice is required, we can
use the negation test to check whether the answer choice in question
is needed for the argument. The reason this works is because the
negation effectively takes the answer choice out of the argument. If
the argument then falls apart, then we know that the answer choice we
negated is required.

(C)'s negation is Franks would not necessarily be assigned the task if
Franks had the assertiveness the task requires. This negation does not
wreck the argument because in the premises, we're given A REASON that
Franks cannot do the assignment. For all we know, there could be other
reasons that Franks cannot do the assignment and other reasons why he
wouldn't be assigned the task. Since (C)'s negation doesn't wreck our
argument, we know that (C) is not a necessary premise, so this answer
choice is out.

(E)'s negation is that someone who is not a supervisor in the shipping
department has the assertiveness the task requires. Ok, but our
argument is not wrecked with this negation. So what if someone else
has the assertiveness required? There could be other requirements as
well in order for someone to be able to do the assignment, so it
doesn't matter if they merely have one of the necessary conditions in
order to complete it. For this reason, we can eliminate (E), as its
negation does not wreck the argument, so we know that it's not a
necessary premise.

Does this make sense? Let us know if you have any more questions!