How many kilograms are in 30.4 lb?
A) 13.8 kg
B) 14 kg
C) 67 kg
D) 66.88 kg
E) 66.9 kg
The correct answer and explanation is :
To convert pounds (lb) to kilograms (kg), we use the conversion factor:
1 pound = 0.453592 kilograms.
Given that you want to convert 30.4 pounds to kilograms, the calculation is as follows:
[
30.4 \, \text{lb} \times 0.453592 \, \text{kg/lb} = 13.8043 \, \text{kg}.
]
Now, rounding this to one decimal place gives:
[
13.8043 \, \text{kg} \approx 13.8 \, \text{kg}.
]
Thus, the correct answer is A) 13.8 kg.
Explanation:
When dealing with unit conversions, it’s essential to know the correct conversion factor. In this case, the conversion factor between pounds and kilograms is crucial. The conversion factor, 0.453592, reflects the exact weight of 1 pound in kilograms. By multiplying the given pounds by this factor, we can convert it directly into kilograms.
The process is straightforward: you multiply the number of pounds (in this case, 30.4) by 0.453592, which gives you the weight in kilograms. The result, 13.8043, is a precise answer, but because the options provided round to one decimal place, the most appropriate rounded answer is 13.8 kilograms.
To ensure accuracy, it’s always essential to keep in mind that conversions should respect significant figures based on the precision of the initial value. Here, the number 30.4 has three significant figures, so the result of the conversion (13.8043) should be rounded to match the same level of precision, which is 13.8 kg.
In summary, converting units is a fundamental skill in science, and understanding how to use conversion factors helps in transforming measurements from one system to another (imperial to metric in this case). Therefore, A) 13.8 kg is the correct and best-rounded answer.