Word Problem, Please Help!

[madeenaa]

Gonzalez Manufacturing borrowed $24000. Part of the money was borrowed at 4%, part at 6%, and part at 8%. The annual interest was $1480, and the total amount borrowed at 4% and 6% was twice the amount borrowed at 8%. Use Gaussian elimination to find the amount borrowed at each rate.

So far I have this, but can't figure out the third equation?:
x + y + z = 24000
.04x + .06y + .08z = 1480

 

[galactus]

Since the amount borrowed at 8% is z, then we have

x+y=2z or x+y-2z=0

That is the third equation

 

[madeenaa]

Thank you so much! What was giving me trouble was the fact that I kept writing (.04x + .06y = 2(.08z)) Now I know what I was doing wrong.
Thanks again...

 

[aruss]

I'm having trouble setting up the following problem, can you help me please?

Anne has $5000 to invest. She invests some at 7% and 6%. After 1 year she has $332 in interest. How much did she invest in each percent?

 

[mmm4444bot]

I'm having trouble setting up the following problem, can you help me please?

Anne has $5000 to invest. She invests some at 7% and 6%. After 1 year she has $332 in interest. How much did she invest in each percent?

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