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1. What annual rate of interest would you have to earn on an investment of $2500 to ensure receiving $182.50 interest after 1 year?

 

2. Phyllis invested $9,000, a portion earning a simple interest rate of 3/2% per year and the rest earning a rate of 2% per year. After one year the total interest earned on these investments was $215.00. How much money did she invest at each rate?

 

Thanks laugh

 Sep 4, 2022
 #1
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1 - 182.50 /2,500 ==0.073  x  100 ==7.3% annual interest rate

 

2 - There is a mistake in this question! One of the interest rates is wrong! Check the numbers carefully.

 Sep 4, 2022
 #2
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Sorry, it's supposed to be 5/2% oops

Thanks for the help!

Guest Sep 4, 2022
 #3
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Let the amount invested at 5/2% ==P

Then, the amount invested at 2% ==9,000  -  P

 

5/2 ==2.5%

 

0.025P  +  0.02 * [9,000  -  P] ==215, solve for P

0.025P  +  180 - 0.02P ==215

0.025P - 0.02P ==215  -  180

0.005P ==35

P ==35 / 0.005 ==$7,000 - invested at 5/2%

9,000  -  7,000 ==$2,000 - inested at 2%

Guest Sep 6, 2022

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