$$2\frac{3}{4} \div 2\frac{2}{3} \div 1\frac{1}{12} = x$$
Aptitude
Simplification
Difficulty: Medium
Choose an option
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A$\frac{39}{48}$
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B$1\frac{1}{4}$
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C$\frac{169}{144}$
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DNone of these
Answer
Correct Answer: None of these
Explanation
Concept & Formula
When handling a chain of continuous division operations with mixed numbers, the standard procedure involves two steps: first, convert every mixed number into an improper fraction. Second, process the chain strictly from left to right, which is mathematically achieved by changing every division sign into a multiplication sign while simultaneously taking the reciprocal of the fraction immediately following it.
Step-by-Step Solution
* **Step 1: Convert all mixed numbers to improper fractions.**
$$2\frac{3}{4} = \frac{4 \times 2 + 3}{4} = \frac{11}{4}$$
$$2\frac{2}{3} = \frac{3 \times 2 + 2}{3} = \frac{8}{3}$$
$$1\frac{1}{12} = \frac{12 \times 1 + 1}{12} = \frac{13}{12}$$
* **Step 2: Rewrite the original equation.**
$$\frac{11}{4} \div \frac{8}{3} \div \frac{13}{12} = x$$
* **Step 3: Convert divisions to multiplications.**
Change each $\div$ to $\times$ and flip the following fraction:
$$x = \frac{11}{4} \times \frac{3}{8} \times \frac{12}{13}$$
* **Step 4: Simplify and Calculate.**
Multiply the numerators together and the denominators together:
$$x = \frac{11 \times 3 \times 12}{4 \times 8 \times 13}$$
Cancel the common factor of $4$ between the numerator ($12$) and denominator ($4$):
$$x = \frac{11 \times 3 \times 3}{1 \times 8 \times 13}$$
$$x = \frac{99}{104}$$
* **Step 5: Verify against options.**
The calculated value is $\frac{99}{104}$. None of the specific options (a, b, c) match this value or can be simplified to this value.
Exam Strategy & Shortcut
Write the expression as a single large fraction immediately: $\frac{11 \times 3 \times 12}{4 \times 8 \times 13}$. Perform cross-cancellations before executing any multiplication. This prevents you from dealing with unnecessarily large numbers like $\frac{396}{416}$, which are highly prone to calculation errors during simplification.
Common Pitfall
The most dangerous pitfall is applying division associatively. If a student calculates the right side first ($2\frac{2}{3} \div 1\frac{1}{12}$) and then divides $2\frac{3}{4}$ by that result, they will arrive at an entirely wrong answer. Continuous division must always be executed from left to right.
Final Answer
Therefore, the correct answer is **None of these**.