Math coin riddle need help please
posted by Maddy .
I have 56 coins consisting of nickels and quarters. The total value of the coins is $5.60. How many of each coin do I have?
Algebra to the rescue...
NN is number of nickles
ND is the number of quarters.
NN*.05 + ND*.25=$5.60
but NN + ND=56
two equations, two unknowns, solve.
its very simple.
let one varible be a representation of the other one.
from there you can plug the equation in.
whenever you have two equations and two variables in each, you follow the steps above to solve them.
How does 42 nickels 14 quarters sound?
n:number of nickels
q:number of quarters
Equation 1: n+q=56
Equation 2: 5n+25q=560
multiply all of Equation 1 by 5>
5n+5q=280
then subtract this new equation from Equation 2
5n+25q=560
5n+5q=280
_________
20q=280
solve for q
q=14
therefore n=42
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