00:01
So this problem gives us a lot of information and asks us to answer several questions.
00:08
So letter a says, did the company make, reduce the amount of lead in its product between march and may? and the answer is yes.
00:16
The pb levels went from 3 .5 to 2 .8 to 2 .4.
00:22
So it was reduced.
00:24
B asks which metal was not reduced, and that would be zinc, because zinc went.
00:30
From 2 .7 to 3 .2 to 3 .7.
00:34
So zinc increased, it was not reduced.
00:37
C says each month's sample represents a different manufacturing process, and which process would you recommend the manufacturer choose to continue to use over the next year while additional processes are tested? and i would recommend mays because the overall amount of metals are the lowest in may.
01:01
Question d asks, what is the total amount of the five metals for the april sample? so we just add all of them up.
01:11
3 .2 plus 2 .8 plus 0 .092 plus 1 .6 plus 292.
01:20
And that gives us 36 .892 milligrams per kilogram.
01:26
And that's our final answer for d.
01:28
Letter e asks, what is the total mass in milligrams of the five? metals for the april sample found in the 1 .00 decimeter squared by 0 .05 0 cm sample.
01:47
And so first we need to find the volume.
01:50
So we'll convert both of these into meters.
01:53
1 .000 0 decimeter squared is 0 .1 meters squared and 0 .05 centimeters square or centimeters is 0 .005 meters.
02:04
And so this gives us a volume.
02:06
Volume of 5 .00 times 10 to the negative 6 meters cubed.
02:13
So now we can take our answer from the previous d36 .892 milligrams per kilogram and find just milligrams.
02:26
So we're given an average density of 800 kilograms per meter cubed.
02:34
And then we can multiply by our volume.
02:38
And then meters cubed cancel, kilograms cancel and we get our answer in milligrams, which is 0 .15 milligrams...