Chapter 5, Problem 15A

Interpretation Introduction

Interpretation: The mass of 1-kg package of hamburger is closest to which of the following needs to be explained.

1. $8\text{oz}$ b. $1\text{lb}$ c. $2\text{lb}$ d. $10\text{lb}$

Concept Introduction: Choose a conversion factor to convert from oz and lb into kg, which cancels the units and omits the units in the result. Conversion factors are the ratios of two parts of the unity report which compares two units. In case of conversion of oz to kg, the conversion factor is $\frac{1\text{kg}}{35.274\text{oz}}$ . And conversion of lb to kg, the conversion factor is $\frac{0.4535\text{kg}}{1\text{lb}}$ .

Answer to Problem 15A

The mass of 1-kg package of hamburger is closest to 2 lb. That is the correct answer is option c.

Explanation of Solution

Convert $\text{2}\text{lb}$ into kg as follows:

  $\begin{array}{c}1\text{lb}=0.4535\text{kg}\\ \text{2}\text{lb}=\text{2}\text{lb}\times \frac{0.4535\text{kg}}{1\text{lb}}\\ =0.907\text{kg}\end{array}$

Therefore, the mass of 1-kg package of hamburger is closest to 2 lb.

Conclusion

In option a convert oz to kg as follows:

  $8\text{oz}\times \frac{1\text{kg}}{35.274\text{oz}}=0.22\text{kg}$

This value is not closest to 1-kg of package of hamburger.

In option b convert lb into kg as follows:

  $1\text{lb}=0.4535\text{kg}$

Hence, this value is not closer to 1-kg of package of hamburger.

In option d convert lb into kg as follows:

  $\begin{array}{c}1\text{lb}=0.4535\text{kg}\\ \text{10}\text{lb}=\text{10}\text{lb}\times \frac{0.4535\text{kg}}{1\text{lb}}\\ =4.535\text{kg}\end{array}$

This value is greater than 1-kg. So, option a, b and d is not closest to 1kg-package.