Self-study
Male boto dolphins often carry objects such as weeds or sticks. ███████████ █████ ███████ ████ ███ ████ █████████ ███ ██ ██ ████ ██████ ██ ██ █ ██████ ████████ ██ ██ ████ ████ ██████ ████ █ ██████ ████████ ██ █████ ██████ ███████ ███ █████████ ██ ██████ ██ ███ █████████ ███ ████ █████ █████ ███
Method of Reasoning
The argument proposes two possible explanations (mating or play) for a phenomenon (carrying objects), and then sets a conditional to evaluate one options (play): if play, then females and kids would do it too. Then, the author negates the necessary condition (females and kids don’t do this) to infer that the sufficient is negated (not play). The author concludes that the remaining option (mating) is the more likely option.
23.
The pattern of reasoning in ███ ████████ █████ ██ ████ ███████ ██ ████ ██ █████ ███ ██ ███ █████████ ██████████
a
If there is █ ███ ██ ███████ ██████ ████ ███████ ████ ████████ ██ ████ ██ ███ ████████ ███ █ ██████ █████ ███████ ██████ ██ ██ ███ ██████████ ███████ ████ ██████ ██ █████
Mismatched premise and conclusion. (A) sets a conditional rule, like the stimulus, but then tries to negate the sufficient (not heavy traffic) to conclude that the necessary will not occur (not late). This is invalid logic, and it is also different from the stimulus, which negates a necessary to conclude that the sufficient is also untrue.
b
I expect the ████████ ██ █████████ ████ ████ ████ ██ █████████ ██ ███ ████████ █████ ████ ███ ████ ██ █████████ ████ ███ ████ ████ ██████████ ██ ███ █████ ██ ██ ██ ██████ ████ ███ ████ ████ ██ ███ █████
Mismatched premise and conclusion. (B) sets a conditional rule, like the stimulus, but then confirms the sufficient (tree is determined to be diseased) to conclude that the necessary will also occur (tree is cut down). The stimulus negates a necessary to conclude that the sufficient is also untrue.
c
If the weather ████████ ██████ ███ █████ █████ ████ █ █████ ████ ████████ ███ ██ ██████ ███ ████ ██ ███ ████████ ██████ ███████ ███ ███ ██████ ███ █████ ██ ██ ██ ██████ ████ ███ ████████ ██████ ███ █████ █████
Mismatched premise and conclusion. (C) sets a conditional rule, like the stimulus, but then confirms the necessary (cancelled trip) to conclude that the sufficient is also true (heavy snow forecast). This is invalid logic, and it is also different from the stimulus, which negates a necessary to conclude that the sufficient is also untrue.
d
If construction of ████ ████████ ████ ██ █████████ ████ █ █████ ██████ ███ ██████████ ██ ████ ████ █████████ ████████ ███ ████ ██ ███ ██████████ ███ ████ ████████ ██ ████████████ ██ ████████ ██████ █████████
The argument sets a conditional rule (if construction...) and then negates the necessary condition (not completed) to infer that the sufficient is negated (not on schedule).
Note, (D) is missing the “two hypotheses” element of the stimulus, but it is the only answer choice that executes the same logic as the stimulus, i.e. negating a necessary in order to negate its sufficient.
e
If Tamika makes █ ███ ████ ██████ █ █████ ██████ ███ ██ █████████ ████████ ███ █████ ██████ ████ ████████ ████ █ ███ ████ ██████ ███ ████ ████████ █████████ ████████
Mismatched premise and conclusion. (E) sets a conditional rule, like the stimulus, but then confirms the sufficient (big sale) to conclude that the necessary will also occur (celebration). The stimulus negates a necessary to conclude that the sufficient is also untrue.