SOLUTION: A jar contains $13.00 in quarters and dimes. If there are 100 coins in total, how many quarters are there in the jar?

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Question 1176816: A jar contains $13.00 in quarters and dimes. If there are 100 coins in total, how many quarters are there in the jar?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Quarters = x
Dimes = y
Number of coins
1.00 x + 1.00 y = 100.00
Amount

25.00 x + 10.00 y = 1300.00
Eliminate y
multiply (1)by -10.00
Multiply (2) by 1.00
-10.00 x -10.00 y = -1000.00
25.00 x 10.00 y = 1300.00
Add the two equations
15.00 x = 300.00
/ 15.00
x = 20.00 - quarters
plug value of x in (1)
1.00 x + 1.00 y = 100.00
20.00 + 1.00 y = 100.00
1.00 y = 80.00
y = 80.00 ---- Dimes