3-5-15
X
00:00
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00:00
CC
The first thing we're going to do with this equation is define
our variables.
So let X equal the amount at 8%, Y equal the amount at 6%, and Z
equal the amount at 9%.
So we know that X + y + Z has to equal 93,000 and the interest .0
eight X + .06 Y plus .09 Z has got equal 7110.
It also tells us the interest or the .08 X of the first one is
three times the interest of the third one so or the second one
so 3 * .06 Y.
Taking all the variables to one side, in that third equation we
get .08 X equaling -.18 Y equaling 0.
So the fact that the third equation doesn't have AZ in it
means I'm going to combine one and two to eliminate the ZI get
a new equation negative .0 One X -, .03 Y equaling negative 1260.
So now I'm going to combine equations 3:00 and 4:00 because
they each only have X&Y, and I end up with Y equaling 24,000.
If we substitute Y into equation three or four because they each
have two variables and we've now solved for one variable, we get
X equal 54,000.
So now we have 2 variables.
So we're going to look for an equation with three variables in
order to solve for the last one.
So we're going to substitute into one or two and we get Z
equal 15,000.
I'm going to leave it to you to do the check and to write the
answer in words.