00:01
So in order to solve this problem, i'm going to create a system of equations.
00:03
Let's first say that i have one alloy that's 21%, or approximately 0 .21 % of copper, plus the other alloy is 60 % or 0 .6.
00:14
If you're not sure how i'm getting this, 21 % divided by 100 and 60 % divided by 100 of the other alloy.
00:22
And i want this to equal 47 pounds, but of, this is the percent equation of 40 percent, so 0 .4, of 40 percent.
00:35
But then my other equation will be how many pounds total? so, x pounds of the 21 percent, y pounds of the 60 percent equals approximately 47.
00:46
Okay.
00:47
So how am i going to solve this? well, there's a couple ways i can use to solve systems.
00:52
I i could do elimination, graphing, substitution.
00:56
I'm going to do elimination to make it easiest.
01:00
Where i add and subtract, so i'm going to multiply my top equation by 10, and i'm going to multiply my bottom equation by 6 to get the same y value.
01:08
So if i multiply by 10 to each value, this will give me 2 .1x plus 6y equals 47 times 0 .4 times 10 will be 188 approximately...