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avatar+1112 

Nancy invested $8,000, some at 5% and some at 9% annual interest. If er combined annual interest is $ 620, find the amount in each account.

 

BOX PROBLEM URGENT!!!!

 May 7, 2019
 #1
avatar+19832 
+2

For how many years is that interest?

I will assume 1 year

x = 5% amount

8000 - x = 9% amount

 

.05 x  + .09 (8000-x ) 620

.05x - .09 x + 720 = 620

-.04x = -100

x = $ 2500  in 5% account       the remainder     8000-2500 = $ 5500 = amount in 9% account

 May 7, 2019
edited by ElectricPavlov  May 7, 2019
 #2
avatar+104882 
+1

Wel...I don't know what a "box problem," is....but....we can still solve this

 

Let the amount invested at 5%  = A

Let the amount invested at 9%  = 8000 - A

 

So.....using   

 

Principal * interstest rate  = interest earned, we have that

 

5% * A + 9% * ( 8000 - A)  =  620

 

.05A + .09 (8000 - A)  = 620        

 

.05A  + 720 - .09A  = 620

 

-.04A + 720 = 620        subtract  720 from each side

 

-.04A  = -100       divide both sides by -.04

 

A = $2500  =  the amount at 5%

Which means that the amount at 9%  = 8000 - 2500 = $5500

 

 

cool cool cool

 May 7, 2019

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