If $2994 \div 14.5 = 172$, then $29.94 \div 1.45 = x$
Aptitude
Decimal Fraction
Difficulty: Easy
Choose an option
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A$0.172$
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B$1.72$
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C$17.2$
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D$172$
Answer
Correct Answer: $17.2$
Explanation
### Concept & Strategy
When adjusting both the dividend and the divisor by decimal shifts, the overall quotient shifts by the net difference in decimal places.
### Step-by-Step Solution
* The given equation can be written as:
$$ \frac{2994}{14.5} = 172 $$
* We need to find the value of:
$$ \frac{29.94}{1.45} $$
* Convert the target decimals using powers of $10$:
$$ \frac{2994 \times 10^{-2}}{145 \times 10^{-2}} $$
Wait, the original denominator is $14.5$. Let us adjust the target fraction to match the known format:
$$ \frac{29.94}{1.45} = \frac{29.94 \times 100}{1.45 \times 10} \times \frac{1}{10} $$
$$ = \frac{2994}{14.5} \times \frac{1}{10} $$
* Substitute the known value ($172$):
$$ 172 \times \frac{1}{10} = 17.2 $$
### Exam Strategy & Shortcut
Compare the new numbers to the old numbers. The dividend ($2994$) becomes smaller by a factor of $100$. The divisor ($14.5$) becomes smaller by a factor of $10$. The net change to the quotient is division by $10$ ($100 \div 10 = 10$). Thus, $172 \div 10 = 17.2$.
### Common Pitfall
Students often apply the $100$ shift and the $10$ shift in the wrong direction, mistakenly arriving at $1.72$ or $1720$. Remember that decreasing the dividend decreases the result, but decreasing the divisor increases the result.
### Final Answer
**Therefore, the correct answer is $17.2$.**