Answer: they have
et n = number of nickels
Let d = number of dimes
given:
(1) +n+%2B+d+=+45+
(2) +5n+%2B+10d+=+360+
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Multiply both sides of (1) by 5
and subtract (1) from (2)
(2) +5n+%2B+10d+=+360+
(1) +-5n+-+5d+=+-225+
+5d+=+135+
+d+=+27+
and, since
(1) +n+%2B+d+=+45+
(1) +n+%2B+27+=+45+
(1) +n+=+45+-+27+
(1) +n+=+18+
She had 18 nickels and 27 dimes
check:
(2) +5%2A18+%2B+10%2A27+=+360+
(2) +90+%2B+270+=+360+
(2) +360+=+360+
Explanation: