Final answer:
The rhetorical device used in the sentence is zeugma, which involves a word that applies to multiple parts of the sentence differently.
Step-by-step explanation:
The rhetorical device illustrated in the bold-faced sentence 'Georgina's patience and her wallet were stretched thin' is a zeugma. This is a figure of speech in which a single word, usually a verb or an adjective, is used to join two or more parts of a sentence, but the word applies to each in a different way. In this example, the verb 'stretched' is used to describe both Georgina's patience and her wallet, implying that both are being extended beyond their capacity. It is not quite literal for patience, indicating a metaphorical or figurative extension, while it is more literal for a wallet, indicating a financial strain.