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Carolyn received a check last week . She invested part at 15% and 1000 more than this amount at 16%. If she will earn $780 in interest in a year, how much was invested at each rate?

 Feb 20, 2020
 #1
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Let the amount invested at  15%  = A

Let the amount invested at  16%  = A + 1000

 

So....

 

Interest   =  Prt        where  t   =1

 

780  = .15A  +  .16 (A + 1000)

 

780  = .15A  + .16A  +  160

 

780   - 160  =  .31A

 

.31A  = 620     

 

A =  620 / .31  =  $2000  at 15%

 

And

 

A + 1000  = $3000 at  16%

 

 

cool cool cool

 Feb 20, 2020

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