SOLUTION: Roberto invested some money at 8%, and then invested $3000 more than twice this amount at 9%. HIs total annual income from the two investments was $3130. How much was invested at 9

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Question 315583: Roberto invested some money at 8%, and then invested $3000 more than twice this amount at 9%. HIs total annual income from the two investments was $3130. How much was invested at 9%? A)$25,000 B)$2500 C)$22,000 D)$9000
I tried by setting my values as follows:
X=.08X
Y=.09Y+3000(.08X)

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
OK, first name your variables.
Let A be the amount at 8%,+B the amount at 9%.
You know the relationship between A and B.
1.B=3000%2B2A
Also you know the total interest from both of the investments.
0.08A%2B0.09B=3130
Multiply both side by 100 to get rid of decimals.
8A%2B9B=313000
Substitute eq. 1 into eq. 2 and solve for A.
8A%2B9%283000%2B2A%29=313000
8A%2B27000%2B18A=313000
26A=286000
highlight%28+A=11000%29
Then from eq. 1,
B=3000%2B2%2811000%29
B=3000%2B22000
highlight%28+B=25000%29