Question 224659:  Jake has 205 coins consisting of nickels, dimes, and quarters. If the total value of the coins is $22 and there are three times as many dimes as nickels, how many of each coin did he have? 
 Answer by drj(1380)      (Show Source): 
You can  put this solution on YOUR website! Jake has 205 coins consisting of nickels, dimes, and quarters. If the total value of the coins is $22 and there are three times as many dimes as nickels, how many of each coin did he have?
 
 
Step 1.  Let x be the number of nickels.
 
 
Step 2.  Let 0.05x be the dollar value of nickels.
 
 
Step 3.  Let y be the number of dimes
 
 
Step 4.  Let 0.10y be the dollar value of dimes.
 
 
Step 5.  Let z be the number of quarters.
 
 
Step 6.  Let 0.25z be the dollar value of quarters.
 
 
Step 7.  Then x+y+z=205 since the total number of coins is 205.
 
 
Step 8.  Then  0.05x+0.10y+0.25z=22 since the dollar value of nickels, dimes, and quarters is 22.
 
 
Step 9.  We are also given y=3x since there are three times as many dimes as nickels.
 
 
Step 10.  Here's our system of linear equations given in Steps 7, 8, and 9.
 
 
   Equation A 
   Equation B 
   Equation C
 
 
Substitute Equation C into Equations A and B
 
 
  or    Equation A1
 
 
  or   Equation B1
 
 
 | Solved by pluggable solver: SOLVE linear system by SUBSTITUTION |  
Solve: 
   We'll use substitution. After moving 1*z to the right, we get: 
   , or  . Substitute that 
  into another equation: 
    and simplify: So, we know that z=25. Since  , x=45. 
   
  Answer:  . 
   |  
  
 
 
With   and    then  
 
 
Check dollar value... ...which is a true statement.
 
 
Step 11.  ANSWER:  The number of nickels is 45, the number of dimes is 135, and the number of quarters is 25.
 
 
I hope the above steps were helpful.
 
 
For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.
 
 
Good luck in your studies!
 
 
Respectfully, 
Dr J
 
 
 
 
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