The value of $$ \frac{489.1375 \times 0.0483 \times 1.956}{0.0873 \times 92.581 \times 99.749} $$ is closest to
Aptitude
Decimal Fraction
Difficulty: Medium
Choose an option
-
A0.006
-
B0.06
-
C0.6
-
D6
Answer
Correct Answer: 0.06
Explanation
### Strategy & Logic
Just like the previous problem, the phrase "closest to" combined with options that differ strictly by a decimal place magnitude ($0.006, 0.06, 0.6, 6$) signals that you should use **Aggressive Approximation**. We need to find the order of magnitude, not the exact digit.
### Step-by-Step Solution
**Given:**
$$ \frac{489.1375 \times 0.0483 \times 1.956}{0.0873 \times 92.581 \times 99.749} $$
**Deduction (Approximation):**
* Round each term to the nearest easy-to-use whole number or clean decimal:
* $489.1375 \approx 500$ (or $490$)
* $0.0483 \approx 0.05$
* $1.956 \approx 2$
* $0.0873 \approx 0.09$ (or $0.1$)
* $92.581 \approx 90$ (or $100$)
* $99.749 \approx 100$
* Let's use these rounded values to rewrite the expression:
$$ \frac{500 \times 0.05 \times 2}{0.09 \times 90 \times 100} $$
* Calculate the approximate numerator:
$500 \times 0.05 = 25$
$25 \times 2 = 50$
* Calculate the approximate denominator:
$0.09 \times 90 = 8.1$
$8.1 \times 100 = 810$
* Evaluate the approximate ratio:
$$ \frac{50}{810} = \frac{5}{81} $$
* Since $5/80$ would be exactly $1/16$, and we know $1/16 = 0.0625$, the value $5/81$ is very close to $0.06$.
* Checking the options, $0.06$ perfectly matches our approximated order of magnitude.
### Exam Strategy & Shortcut
**Magnitude Tracking:** You can simplify the order of magnitude visually.
Numerator is roughly: $500 \times (5 \times 10^{-2}) \times 2 = 50$.
Denominator is roughly: $(1 \times 10^{-1}) \times 100 \times 100 = 1000$.
$50 / 1000 = 0.05$.
The closest option to $0.05$ is $0.06$. This confirms that the magnitude is in the hundredths place, instantly eliminating $0.006, 0.6,$ and $6$.
### Common Pitfall
Rounding down too many terms in the denominator (e.g., making it $0.08 \times 90 \times 90$) while rounding up the numerator. This can skew your final fraction slightly. Always try to round one term up and another down to balance the error, though in magnitude-based questions, minor skewing rarely changes the final answer.
### Final Answer
**Therefore, the correct answer is 0.06.**