$\frac{2}{2 + \frac{2}{3 + \frac{2}{3 + \frac{2}{3}}}} \times 0.39$ is simplified to
Aptitude
Simplification
Difficulty: Hard
Choose an option
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A\frac{1}{3}
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B2
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C6
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DNone of these
Answer
Correct Answer: 2
Explanation
### Concept & Strategy
This problem features a deeply nested continued fraction alongside decimal multiplication.
**Important Note on Typography:** In typical aptitude tests, a multiplier placed alongside the main denominator bar (like the $\times 0.39$ here) implicitly applies to that entire evaluated denominator grouping. Thus, the expression we are evaluating is mathematically represented as $\frac{2}{(2 + \dots) \times 0.39}$. The strategy is to simplify the continued fraction first, multiply the denominator by 0.39, and finally divide the numerator.
### Step-by-Step Solution
Let's simplify the continued fraction in the denominator from the bottom up.
* **Step 1: Lowest level**
$$3 + \frac{2}{3} = \frac{9 + 2}{3} = \frac{11}{3}$$
* **Step 2: Second level**
Substitute and invert:
$$\frac{2}{\frac{11}{3}} = \frac{6}{11}$$
Add to 3:
$$3 + \frac{6}{11} = \frac{33 + 6}{11} = \frac{39}{11}$$
* **Step 3: Third level**
Substitute and invert:
$$\frac{2}{\frac{39}{11}} = \frac{22}{39}$$
Add to 2 (completing the bracketed denominator):
$$2 + \frac{22}{39} = \frac{78 + 22}{39} = \frac{100}{39}$$
* **Step 4: Apply the Decimal Multiplication**
Now, multiply this evaluated denominator by $0.39$. It is easier to convert $0.39$ to a fraction:
$$0.39 = \frac{39}{100}$$
Multiplying them together:
$$\frac{100}{39} \times \frac{39}{100} = 1$$
* **Step 5: Final Evaluation**
Substitute the final denominator value back under the main numerator:
$$\frac{2}{1} = 2$$
### Exam Strategy & Shortcut
Look for cancellation opportunities! Once you see the denominator simplifying to $\frac{100}{39}$ and notice the multiplier is $0.39$, you should immediately recognize that $0.39 = 39/100$. These numbers are perfectly designed to cross-cancel to 1. Spotting these relationships prevents unnecessary and error-prone decimal division.
### Common Pitfall
Misinterpreting the position of $\times 0.39$. If you multiply the *entire evaluated fraction* by 0.39 (i.e., treating it as $\frac{2}{100/39} \times 0.39$), you would get $0.78 \times 0.39 = 0.3042$, which isn't an option. Always look closely at the horizontal alignment of the arithmetic operators in poorly typeset exams.
### Final Answer
Therefore, the correct answer is **2**.