Question

Difficulty: HardNecessary Assumption

Consider the following argument:

City Council Member: Our city's public transit system is currently operating at a significant financial deficit. To eliminate this deficit, the transit authority has proposed a 20 percent increase in all bus and subway fares. However, our studies indicate that this fare increase will cause a 25 percent drop in total ridership as commuters switch to other modes of transportation. Therefore, implementing the fare increase will actually worsen the transit system's financial deficit rather than eliminate it.

The argument above necessarily assumes that the transit system's operating costs will not decrease sufficiently to offset the lost revenue when ridership drops by 25 percent.

Answer: Answer

Answer

True
The statement is a strictly necessary assumption because the argument equates a loss in revenue with an increased deficit. This jump in logic requires the author to assume that operating costs will not drop enough to offset the lost revenue. If we negate the assumption and imagine that costs DO drop significantly alongside ridership, the conclusion fails.

Step-by-Step Solution

1
Identify the argument's main conclusion.
The conclusion is: 'implementing the fare increase will actually worsen the transit system's financial deficit rather than eliminate it.'
Isolating the conclusion is the critical first step in evaluating any Logical Reasoning argument.
2
Identify the premises supporting the conclusion.
The premises are: Fares will increase by 20%, but ridership will drop by 25%.
Understanding the evidence provided helps identify the logical gap in the author's reasoning.
3
Analyze the conceptual gap between the premises and the conclusion.
The premises prove that total revenue will decrease. However, the conclusion makes a claim about a 'financial deficit', which is determined by both revenue and operating costs.
Many logical flaws rely on shifting terms—in this case, treating a loss in revenue as identical to an increase in deficit.
4
Apply the Negation Test to the provided assumption statement.
Negated statement: 'The transit system's operating costs WILL decrease sufficiently to offset the lost revenue.' If this negated statement were true, the deficit would not worsen, which directly destroys the author's conclusion.
The Negation Test definitively proves whether an assumption is strictly required for the argument to survive.

Key Concept

Necessary Assumptions and the Negation Test
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