SOLUTION: Theresa has 20 coins that are dimes ans quarters. Together they equal $2.75. How many of each type of coin doe she have?

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
.
q+d = 20
q = 20-d
.
25q + 10d = 275 cents
.
substitute
.
25(20-d) + 10d = 275
500 - 25d +10d = 275
-15d = -225
d = 15
.
q = 20-15
q = 5
.
Check the value
10*15 = 150 cents
25*5 = 125 cents
150+125 = 275 cents
Correct.
.
Answer: 15 dimes + 5 quarters
.
Done.
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