- #1
s2huang
- 2
- 0
Homework Statement
We were asked to solve it using Augmented matrix. I just need one more equation though.
A jar of coins contains only dimes, nickels, and pennies. There are 98 coins in the jar, and the total value of the coins is $6.49.
Set up the system of equations representing this system, in the variables d, n, and p.
Homework Equations
1 dime = 10 cents
1 nickel = 5 cents
1 penny = 1 cent
The Attempt at a Solution
I set up two equations:
d+n+p = 98
10d + 5n + p = 649
but I can't find the third equation.
p is a free variable.
the 9 in 649 is the clue i think because only nickels and pennies can add up to 9
and there are two possible ways:
1 nickel + 4 pennies, OR
9 pennies
So d and n depend on p but I don't know how to express it in an equation.
I tried 5n+p=9 but it didn't work.
I tried to substitute 5n=9-p for n, but then it's not linear algebra and the answer was not correct.