SOLUTION: A parking meter contains dimes and quarters worth $5.05. There are 28 coins in all. Find how many of each there are are.

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Question 810501: A parking meter contains dimes and quarters worth $5.05. There are 28 coins in all. Find how many of each there are are.
Found 2 solutions by josmiceli, richwmiller:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +d+ = numbe of dimes
Let +q+ = number of quarters
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(1) +d+%2B+q+=+28+
(2) +10d+%2B+25q+=+505+ ( in cents )
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Multiply both sides o (1) by +10+
and subtract (1) from (2)
(2) +10d+%2B+25q+=+505+
(1) +-10d+-+10q+=+-280+
+15q+=+225+
+q+=+15+
and, since
(1) +d+%2B+q+=+28+
(1) +d+=+13+
There are 13 dimes and 15 quarters
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check:
(2) +10d+%2B+25q+=+505+
(2) +10%2A13+%2B+25%2A15+=+505+
(2) +130+%2B+375+=+505+
(2) +505+=+505+
OK

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
25q+10d=505,
d+q=28
d=28-q
5q+2d=101
5q+2*(28-q)=101
5q+56-2q=101
3q=45
q=15
d=13
check
15*25+13*10=505
375+130=505
505=505
ok