Question 92465
Write an equation for each statement:
:
"A man has 29 coins in his pocket, all of which are dimes and quarters. "
    d + q = 29
:
"If the total value of his change is 590 cents,"
 10d + 25q = 590
:
how many dimes and how many quarters does he have?
Using the first equation:
d + q = 29
d = (29 - q)
:
Substitute (29-q) for d in the 2nd equation:
10(29-q) + 25q = 590
290 - 10q + 25q = 590
-10q + 25q = 590 - 290
15q = 300
q = 300/15
q = 20 quarters
:
d = 29 - 20
d = 9 dimes
:
Check solutions: 10(9) + 25(20) = 590

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