Directions: Each of the questions below consists of a statement and/or a question and two statements labelled I and II given below it. You have to decide whether the data provided in the statements is/are sufficient to answer the question. Read both the statements and Give answer (a) if the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question; Give answer (b) if the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question; Give answer (c) if the data either in Statement I or in Statement II alone are sufficient to answer the question; Give answer (d) if the data even in both Statements I and II together are not sufficient to answer the question; and Give answer (e) if the data in both Statements I and II are necessary to answer the question. What is the value of $a$? I. Ratio of $a$ and $b$ is $3 : 5$, where $b$ is positive. II. Ratio of $2a$ and $b$ is $12 : 10$, where $a$ is positive.
Verbal Reasoning
Data Sufficiency
Difficulty: Medium
Choose an option
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Aif the data in Statement I alone are sufficient to answer the question, while the data in Statement II alone are not sufficient to answer the question
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Bif the data in Statement II alone are sufficient to answer the question, while the data in Statement I alone are not sufficient to answer the question
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Cif the data either in Statement I or in Statement II alone are sufficient to answer the question
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Dif the data even in both Statements I and II together are not sufficient to answer the question
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Eif the data in both Statements I and II are necessary to answer the question
Answer
Correct Answer: if the data even in both Statements I and II together are not sufficient to answer the question
Explanation
### Concept & Redundant Information
To find a specific numerical value for a variable, you need an equation that connects it to a known constant. Ratios only provide relationships between variables, not their absolute values.
### Step-by-Step Solution
* **Analyzing Statement I:**
* We are given $\frac{a}{b} = \frac{3}{5}$. This means $a = \frac{3}{5}b$.
* Because $b$ is an unknown positive number, $a$ can be any positive number.
* Statement I is not sufficient.
* **Analyzing Statement II:**
* We are given $\frac{2a}{b} = \frac{12}{10}$.
* Simplifying the right side: $\frac{2a}{b} = \frac{6}{5}$.
* Dividing by 2: $\frac{a}{b} = \frac{3}{5}$.
* This is the exact same ratio provided in Statement I. It still does not yield an absolute numerical value for $a$.
* Statement II is not sufficient.
* **Combining Both Statements:**
* Since both statements provide identical mathematical information ($\frac{a}{b} = \frac{3}{5}$), combining them does not give us any new equations to solve for the exact value of $a$.
### Exam Strategy & Shortcut
Recognize when statements are just different expressions of the exact same fact. If statement I doesn't work and statement II is mathematically identical, combining them will never work either.
### Common Pitfall
A common error is assuming that $a$ strictly equals 3 just because the ratio is $3:5$. A ratio defines proportions, so $a$ could be 3, 6, 9, 30, etc.
### Final Answer
Therefore, the correct answer is **if the data even in both Statements I and II together are not sufficient to answer the question**.