Self-study
Support The photographs that the store developed were quite unsatisfactory. ███ ████████ ██████ ██ ████ ███████ ███ ████ ██████████ ███████ ███ ████ ███ ███ ██████ ███ ██████████ ██ █ █████ ████ ███ ███████ ████████ █████████ ███ ████████ ██ ████ █ ███████ ██ ██ ███ ██████████ █████ ██ ████████ ███ █████ ████ ███ █ ███████
Summary
The author concludes that if the customer’s claim that she handled the film correctly is true, then the store owes her a refund.
Why?
Because if a store does not process pictures properly, the customer is owed a refund.
The photos the store developed were unsatisfactory. And neither the film nor the camera were defective.
Notable Assumptions
The author assumes that if neither the film nor the camera are defective, and the customer handled the film correctly, and the photos developed by the store are unsatisfactory, then the store did not process the pictures properly. (In other words, the author assumes that the sufficient condition of the rule “store didn’t process pictures properly → owe refund” is triggered.)
7.
The argument relies on assuming █████ ███ ██ ███ ██████████
a
If the store ████ ███ ████████ █ ███████ ████ ███████ ███ ██████ ███ ███ ████ ███ ██████████
Not necessary, because the author’s trying to prove that the store owes the customer a refund (if what the customer said is correct). That doesn’t require the author to believe something about what must be true IF the store owes the customer a refund.
b
If neither the ████ ███ ███ ██████ ███ ██████████ ███ ███ ████████ ███████ ███ ████ ██████████ ████ ███ █████ █████████ ██ ███████████
Necessary, because the author must assume that the facts she presented are enough to trigger the rule for when the store owes a refund. If (B) were not true, then we wouldn’t be able to infer that the store process the film improperly, and then we wouldn’t be able to conclude that the customer is owed a refund.
c
If pictures are █████ ████ █ █████████ ███████ ████ ██ ██ ███ ████████ ███ ███ █████ ██ ███████ █████ ████████ ███████████
Not necessary, because (C) is a rule concerning when the store could NOT have processed pictures IMproperly (meaning, did process them properly). But the author must assume that the store did NOT process the film properly.
d
If the customer ███████ ███ ████ ████████████ ████ ██ ████ ██████ ███ ███████████ ████ ███ █████ █████████ ██ ██ ███████████████
Not necessary, because for the purpose of the conclusion, we are accepting that the customer DID handle the film correctly.
e
If the customer's █████ ███ ███ ████████ ████ ███ █████ ████ ███ ███ ███ █ ███████
Not necessary, because for the purpose of the conclusion, we’re accepting what the customer said is correct.