SOLUTION: A collection of coins consisting of dimes and quarters amounts to $5.35. Twice the number of dimes exceeds the number of quarters by 5. Find the number of each kind of coin.

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: A collection of coins consisting of dimes and quarters amounts to $5.35. Twice the number of dimes exceeds the number of quarters by 5. Find the number of each kind of coin.      Log On


   



Question 232942: A collection of coins consisting of dimes and quarters amounts to $5.35. Twice the number of dimes exceeds the number of quarters by 5. Find the number of each kind of coin.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let d = number of dimes
Let q = number of quarters
given:
(1) 10d+%2B+25q+=+535 (in cents)
(2) 2d+=+q+%2B+5
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This is 2 equations and 2 unknowns, so it's solvable
Subtract q from both sides of (2)
(2) 2d+-+q+=+5
Now multiply both sides by 5
and subtract (2) from (1)
(1) 10d+%2B+25q+=+535
(2) -10d+%2B+5q+=+-25
30q+=+510
q+=+17
and, since
(2) 2d+=+q+%2B+5
2d+=+17+%2B+5
2d+=+22
d+=+11
There are 17 quarters and 11 dimes
check:
(1) 10d+%2B+25q+=+535
10%2A11+%2B+25%2A17+=+535
110+%2B+425+=+535
535+=+535
OK