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You have a jar containing 39 coins , consisting entirely of nickels and dimes , worth a total of $2.55. How many nickels are in the jar

 Mar 31, 2020
 #1
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Let  N  be  the  number of nickels in the jar

Then 39 - N  = the  number of dimes

 

And  we  have that

 

N*(.05)  + (39 - N) *.10  = 2.55    simplify

 

.05N  + 3.9 - .10N  = 2.55  

 

-.05N  + 3.9  = 2.55     subtract  3.9  from both sides

 

-.05N =  -1.35    divide both sides by -.05

 

N  = 27   =  number of  nickels

 

cool cool cool

 Mar 31, 2020

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