0:00
All righty.
00:01
So for this problem, it takes a little bit of some steps to get this done.
00:04
I know there's 20 coins total that are dimes and quarters.
00:07
So we use d for dimes, q for quarters.
00:10
So however many dimes and however many quarters are going to add up to 20 coins in someone's purse or pocket or whatever.
00:18
And their value total to be 425.
00:21
Now we know dimes are worth 10 cents.
00:24
So we'll put point 10d.
00:27
And we know quarters are worth 25.
00:29
So 0 .25q is equal to $4 .25.
00:35
Now, this is called a system of equations, but we can get it to where it gets down to being 1.
00:41
And so what i'm going to do is i'm going to move this d over here by doing traction.
00:46
So now i have q is equal to 20 minus d.
00:49
So i still have this point 10 here.
00:53
I have this point to 5.
00:55
And then instead of having q get written down, i'm going to replace this or substituted in for 20 minus d equals 425...