Question

In the metric system, 1 gran is the mass of 1 milliliter of water. So, a 2-liter bottle of water has a mass of 2 kilograms. A gallon of water weighs about 8 pounds. What is the mass of a gallon of water to the nearest tenth of a kilogram?Parts A-D

Answer 1

We know that:

`1\text{ lb }\to0.45\text{ kg}`

A)

Using the conversion law, we can calculate the conversion factor as a fraction:

`\frac{0.45\text{ kg}}{1\text{ lb}}=\frac{9\text{ kg}}{20\text{ lb}}`

B)

Now, we multiplicate 8 pounds by the conversion factor:

`\frac{9\text{ kg}}{20\text{ lb}}\cdot8\text{ lb }\approx3.6\text{ kg}`

C)

The pound units cancel, resulting in an answer given in kilograms.

D)

When you choose a conversion factor, the unit you are converting to is the first quantity in the rate.