Question

Question #f2241

Answer 1

Multiply out the package mass by a ratio of ounces-to-pounds to get:

`m = 12.5 lb * (16 oz.)/(1 lb) = 200 oz.`

Explanation:

Let's see what we have:

m = `12.5 lb`

And we want to convert it to ounces. Well, we know that

`1 lb = 16 oz.`

And therefore, dividing both sides by `1 lb`:

`1 = (16 oz.)/(1 lb)`

Now, here's what I'm after: I'm going to multiply our package mass in pounds, by one, which we will replace with this new ratio we have, so that it goes from pounds to ounces.

First, multiply by one, because that doesn't change the number:

`m = 12.5 lb * 1`

And, by our new ratio, we get that `1` is equal to `(16 oz.)/(1 lb)`, so, substitute that in:

`m = 12.5 lb * (16 oz.)/(1 lb)`

We can see that the `lb` unit cancels out:

`m = 12.5 * (16 oz.)/1`

Division by one doesn't change anything:

`m = 12.5 * 16 oz.`

And now we can multiply:

`m = 200 oz.`

Therefore, `12.5 lb = 200 oz.`, and the package has a mass of 200 ounces.