# Math Help - Word Problem Using Cramer's Rule

1. ## Word Problem Using Cramer's Rule

Hi folks,
My instructor has given us an extra credit sheet and it has this word problem that must be solved using cramer's rule. I know how to apply or solve using cramer's rule but I can't seem to properly create a system of equations. Maybe you guys could help me.

Jenny receives $1,270 per year from three different investments totaling$20,000. One of the investments pays 6%, the second one pays 8%, and the third one pays 5%. If the money invested at 8% is $1,500 less than the amount invested at 5%, how much money has jenny invested in the investment that pays 6%? 2. Originally Posted by chipman316 Hi folks, My instructor has given us an extra credit sheet and it has this word problem that must be solved using cramer's rule. I know how to apply or solve using cramer's rule but I can't seem to properly create a system of equations. Maybe you guys could help me. Jenny receives$1,270 per year from three different investments totaling $20,000. One of the investments pays 6%, the second one pays 8%, and the third one pays 5%. If the money invested at 8% is$1,500 less than the amount invested at 5%, how much money has jenny invested in the investment that pays 6%?
Hi chipman36,

This is how it shapes up to me:

Let x = amount invested at 6%
Let y = amount invested at 8%
Let z = amount invested at 5%

Total amount used to invest = 20000:
[1] $x+y+z=20000$

Annual return on investments:
[2] $.06x+.08y+.05z=1270$

Amount invested at 8% is \$1,500 less than the amount invested at 5%
[3] $y=z-1500$

3. Thank you so much. The last system was really throwing me off. Simple subtraction I know but I somehow kept trying several different things only to get negative investment numbers. Thanks again!