SOLUTION: A person has 20 coins, all nickels and dimes, worth $1.65. How many nickels are there

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Question 872392: A person has 20 coins, all nickels and dimes, worth $1.65. How many nickels are there
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +n+ = number of nickels
Let +d+ = number of dimes
--------------------------
(1) +n+%2B+d+=+20+
(2) +5n+%2B+10d+=+165+ ( in cents )
--------------------------------
(2) +n+%2B+2d+=+33+
Subtract (1) from (2)
(2) +n+%2B+2d+=+33+
(1) +-n+-+d+=+-20+
-------------------
+d+=+13+
and, since
(1) +n+%2B+d+=+20+
(1) +n+%2B+13+=+20+
(1) +n+=+7+
There are 7 nickels and 13 dimes
check:
(2) +5n+%2B+10d+=+165+
(2) +5%2A7+%2B+10%2A13+=+165+
(2) +35+%2B+130+=+165+
(2) +165+=+165+
OK