SOLUTION: Fill in the blanks. Mrs. Brighton invested $30,000 and received a total of $2,300 in interest. She invested part of the money at 10% and the remainder at 5%. She invested $____

Algebra ->  Probability-and-statistics -> SOLUTION: Fill in the blanks. Mrs. Brighton invested $30,000 and received a total of $2,300 in interest. She invested part of the money at 10% and the remainder at 5%. She invested $____      Log On


   



Question 316829: Fill in the blanks.
Mrs. Brighton invested $30,000 and received a total of $2,300 in interest. She invested part of the money at 10% and the remainder at 5%. She invested $_______ at 10% and $_________ at 5%

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the amount at 10%, B the amount at 5%.
Total amount
1.A%2BB=30000
Total interest
2.0.10A%2B0.05B=2300
Multiply eq. 2, by (-10) and add to eq. 1,
A%2BB-A-0.5B=30000-23000
0.5B=7000
highlight%28+B=14000%29
Then from eq. 1,
A%2B14000=30000
highlight%28+A=16000%29
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She invested $16,000 at 10% and $14,000 at 5%.