Question 290924:  Hello all, I am struggling with the following problem. I know it is probably really easy and im just not understanding something, but I keep getting stuck on how to express the variable for calculating the amount of each coin and there $ value in each equation. Any help will be great. 
A jar contains 100 coins made up of 50 cent coins and 20 cent coins. How many coins are there if the total value of the coins is $38.00. Solve algebraically. 
a) Express this problem as a system of two equations. Define variables correctly. 
b) Solve system of equations simultaneously.
 
Thanks, -Nick. 
 Answer by stanbon(75887)      (Show Source): 
You can  put this solution on YOUR website! A jar contains 100 coins made up of 50 cent coins and 20 cent coins. How many coins are there if the total value of the coins is $38.00. Solve algebraically. 
a) Express this problem as a system of two equations. Define variables correctly. 
Quantity Eq:::: f + t = 100 
Value Eq::::: 50f + 20t = 3800 cents 
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b) Solve system of equations simultaneously.  
Multiply thru the 1st Eq by 20: 
20f + 20t = 20*100 
50f + 20t = 3800 
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Subtract 1st from 2nd and solve for "f": 
30f = 1800 
f = 60 (# of first cent coins) 
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Since f + t = 100, t = 40 (# of twenty cent coins) 
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Cheers, 
Stan H. 
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