A sum of ₹ 6400 is divided among three workers in the ratio $\frac{3}{5} : 2 : \frac{5}{3}$. The share (in rupees) of the second worker is (S.S.C., 2007)
Aptitude
Ratio and Proportion
Difficulty: Easy
Choose an option
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A2560
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B3000
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C3200
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D3840
Answer
Correct Answer: 3000
Explanation
### Concept & Simplifying Fractional Ratios
To divide a total sum based on a ratio containing fractions, you must first convert the fractional ratio into an equivalent integer ratio by multiplying all terms by the Least Common Multiple (LCM) of the denominators.
$$ \text{Equivalent Integer Ratio} = \text{Fractional Ratio} \times \text{LCM}(\text{Denominators}) $$
### Step-by-Step Solution
1. **Identify the fractional ratio:**
The given ratio is $\frac{3}{5} : 2 : \frac{5}{3}$
Note that $2$ can be written as $\frac{2}{1}$. Denominators are 5, 1, and 3.
2. **Find the LCM:**
The LCM of 5 and 3 is 15.
3. **Convert to an integer ratio:**
Multiply each term in the ratio by 15:
First term: $\frac{3}{5} \times 15 = 3 \times 3 = 9$
Second term: $2 \times 15 = 30$
Third term: $\frac{5}{3} \times 15 = 5 \times 5 = 25$
The simplified ratio is $9 : 30 : 25$.
4. **Calculate the share of the second worker:**
Total ratio parts = $9 + 30 + 25 = 64$.
Total sum = ₹ 6400.
Second worker's share = $\frac{30}{64} \times 6400$
Second worker's share = $30 \times 100 = 3000$.
### Exam Strategy & Shortcut
Recognize immediately that the sum of the integer ratio parts ($9 + 30 + 25 = 64$) matches the significant digits of the total amount ($6400$). This makes the multiplier exactly $100$. You can instantly see the second worker's share is $30 \times 100 = 3000$ without writing out the full division.
### Common Pitfall
Forgetting to multiply the middle integer ($2$) by the LCM. Students often just multiply the fractions by the LCM and leave the integer as $2$, incorrectly creating the ratio $9 : 2 : 25$.
### Final Answer
Therefore, the correct answer is **3000**.