SOLUTION: Ben has $3.40 consisting of quarters and dimes. How many coins of each kind does he have if he has 22 coins?

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Question 760998: Ben has $3.40 consisting of quarters and dimes. How many coins of each kind does he have if he has 22 coins?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
10 quarters and 12 dimes =
+10%2A25+%2B+12%2A10+=+250+%2B+120+
+250+%2B+120+=+370+
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9 quarters and 13 dimes =
+9%2A25+%2B+13%2A10+=+225+%2B+130+
+225+%2B+130+=+355+
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8 quarters and 14 dimes =
+8%2A25+%2B+14%2A10+=+200+%2B+140+
+200+%2B+140+=+340+
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He has 8 quarters and 14 dimes
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also, you can say:
Let +d+ = number of dimes he has
Let +q+ = number of quarters he has
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(1) +d+%2B+q+=+22+
(2) +10d+%2B+25q+=+340+ ( in cents )
Multiply both sides of (1) by +10+
and subtract (1) from (2)
(2) +10d+%2B+25q+=+340+
(1) +-10d+-+10q+=+-220+
+15q+=+120+
+q+=+8+
and
(1) +d+%2B+q+=+22+
(1) +d+=+14+
Same answer