Question 505040: Theresa has 20 coins that are dimes ans quarters. Together they equal $2.75. How many of each type of coin doe she have? Answer by oberobic(2304) (Show Source):
You can put this solution on YOUR website! With coin problems you have to keep track of the number of each type of coin and their values.
q = number of quarters
25q = value of quarters
d = number of dimes
10d = value of dimes
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q+d = 20
q = 20-d
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25q + 10d = 275 cents
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substitute
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25(20-d) + 10d = 275
500 - 25d +10d = 275
-15d = -225
d = 15
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q = 20-15
q = 5
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Check the value
10*15 = 150 cents
25*5 = 125 cents
150+125 = 275 cents
Correct.
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Answer: 15 dimes + 5 quarters
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Done.
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