SOLUTION: A collection of nickels, dimes, and quarters consists of 13 coins with a total value of $1.50. If the number of dimes is equal to the number of nickels, find the number of each typ

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: A collection of nickels, dimes, and quarters consists of 13 coins with a total value of $1.50. If the number of dimes is equal to the number of nickels, find the number of each typ      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


   



Question 798210: A collection of nickels, dimes, and quarters consists of 13 coins with a total value of $1.50. If the number of dimes is equal to the number of nickels, find the number of each type of coin.
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
Let +q+ = number of quarters
----------------------------
(1) +n+%2B+d+%2B+q+=+13+
(2) +5n+%2B+10d+%2B+25q+=+150+ ( in cents )
(3) +d+=+n+
----------------
This is 3 equations and 3 unknowns,
so it's solvable
Substitute (3) into both (1) and (2)
(1) +n+%2B+n+%2B+q+=+13+
(2) +5n+%2B+10n+%2B+25q+=+150+
---------------------------
(1) +2n+%2B+q+=+13+
(2) +15n+%2B+25q+=+150+
multiply both sides of (1) by +25+
and subtract (2) from (1)
(1) +50n+%2B+25q+=+325+
(2) +-15n+-+25q+=+-150+
+35n+=+175+
+n+=+5+
and, since
(3) +d+=+n+
+d+=+5+
and
(1) +5+%2B+5+%2B+q+=+13+
(1) +10+%2B+q+=+13+
(1) +q+=+3+
There are 5 nickels
There are 5 dimes
There are 3 quarters
check:
(2) +5%2A5+%2B+10%2A5+%2B+25%2A3+=+150+
(2) +25+%2B+50+%2B+75+=+150+
(2) +150+=+150+
OK