If $\sqrt{6} = 2.449$, then the value of $\frac{3\sqrt{2}}{2\sqrt{3}}$ is
Aptitude
Square Root and Cube Root
Difficulty: Medium
Choose an option
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A0.6122
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B0.8163
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C1.223
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D1.2245
Answer
Correct Answer: 1.2245
Explanation
### Concept & Formula
Simplify surds and fractions by rationalizing the denominator or by cancelling common radical factors between the numerator and the denominator.
$$ \frac{\sqrt{a}}{\sqrt{b}} = \sqrt{\frac{a}{b}} $$
### Step-by-Step Solution
Given: $\sqrt{6} = 2.449$
We need to evaluate the expression:
$\frac{3\sqrt{2}}{2\sqrt{3}}$
Let's simplify the fraction by splitting the integers from the radicals:
$\frac{3}{2} \times \frac{\sqrt{2}}{\sqrt{3}}$
To eliminate the square root in the denominator, rationalize it by multiplying the top and bottom by $\sqrt{3}$:
$\frac{3 \times \sqrt{2} \times \sqrt{3}}{2 \times \sqrt{3} \times \sqrt{3}}$
Combine the radicals in the numerator ($\sqrt{2} \times \sqrt{3} = \sqrt{6}$) and simplify the denominator ($\sqrt{3} \times \sqrt{3} = 3$):
$\frac{3 \times \sqrt{6}}{2 \times 3}$
The $3$ in the numerator and the $3$ in the denominator cancel each other out:
$\frac{\sqrt{6}}{2}$
Substitute the given value for $\sqrt{6}$:
$\frac{2.449}{2}$
Perform the division:
$2.449 \div 2 = 1.2245$
### Exam Strategy & Shortcut
Recognize that $3$ is simply $(\sqrt{3})^2$. So, $\frac{3}{\sqrt{3}}$ instantly simplifies to $\sqrt{3}$.
The expression becomes $\frac{\sqrt{3} \times \sqrt{2}}{2}$, which is $\frac{\sqrt{6}}{2}$.
Divide $2.449$ in half to get $1.2245$. This takes fewer than ten seconds.
### Common Pitfall
Substituting approximate values for $\sqrt{2}$ ($1.414$) and $\sqrt{3}$ ($1.732$) directly into the initial expression creates a messy calculation ($3 \times 1.414 / 2 \times 1.732$) and amplifies rounding errors.
### Final Answer
Therefore, the correct answer is **1.2245**.