00:01
For this problem, we have that a patient is to receive 0 .25 milligrams per kilogram of medication per day.
00:11
So what that means is for each kilogram that the person weighs, they are to receive 0 .25 milligrams of the medication.
00:21
Now, the patient is a 220 pound man.
00:25
So we have his weight in pounds.
00:28
There is some conversions that we're going to have to do to determine how much medication he will need in milligrams.
00:37
So useful info that we'll be using in our calculations is written right here.
00:44
One kilogram is approximately 2 .205 pounds.
00:49
So that's what we'll do first.
00:51
We will first convert his weight from pounds into kilograms.
00:57
Okay, so let's do that.
01:00
One way that i like to do conversions, just to keep track of all the units, is to write out some fractions.
01:09
We have a 220 -pound man.
01:12
So i'll write that down, 220 pounds with the units.
01:16
And then i'm going to times it by a fraction.
01:19
So the fraction is going to involve what i have here in bread, the useful information.
01:25
I'm going to have the kilograms, 1 kilograms somewhere, and then the 2 .205 pounds somewhere.
01:31
Now how do i know which one to put on top of my fraction? well, i definitely want pounds to cancel out with pounds.
01:41
So imagine that this is a fraction as well.
01:44
Over 1.
01:45
I want pounds to be on the top here, pounds to be on the bottom there.
01:50
Okay, so if that's the case, i'm going to put pounds on bottom of my fraction, kilograms on top.
01:55
So it's one kilogram for every 2 .205 pounds.
02:01
And this setup right here is what i like to use to keep, again, keep track of all of the different units that are changing.
02:10
So we have this 220 pound person, times it by this fraction here.
02:19
And then just remember when you're timesing fractions, timesing straight across.
02:24
So it's 220 over 2 .205 pounds get canceled out, which that's what i wanted, because i wanted kilograms as my units...