# Math coin riddle need help please

posted by
**Maddy** on
.

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