00:01
Hello.
00:03
So we are going to start with the number of 1 ,200 milligrams of calcium needed per day for a person and see how many cups of milk that would be equivalent to.
00:18
Right.
00:19
So we're going to do it a dimensional analysis.
00:22
And so our second fraction then needs to have milligrams of calcium in it because it needs to cancel.
00:27
And that is where the sentence that one cup of milk has 290 milligrams of calcium, we can make a conversion factor out of that.
00:37
We can put the 290 milligrams on the bottom.
00:41
We'll do that because we want those milligrams to cancel with the one above.
00:44
And then on top, do one cup.
00:49
The milligrams cancel.
00:51
Now we're just in cups.
00:53
Now they did tell us how many milliliters are in a cup, so we can do one more conversion factor.
00:59
We'll put one cup on the bottom, and then on top put those milliliters, the 236 .58 milliliters.
01:09
And that'll convert us into milliliters.
01:12
The cups cancel, and all that's left then is to do the math, which would be 1 ,200 divided by 290 times 236 .58.
01:24
And i get a value of 979 milliliters.
01:30
There was the note to do it with only two significant figures.
01:35
If we needed to limit this to two, you'd have to round that seven up, so it would be like 980 milliliters, or you could even put it in scientific notation and do 9 .8 times 10 to the 2 milliliters.
01:48
Any of those answers are fine.
01:50
The bottom two have the right number of sick figs that they wanted.
01:54
All right...