Question

A handful of 65 coins consist of pennies, nickels and dimes. The number of nickels is 4 less than twice of pennies, and there are 13 more dimes than nickels. How many coins of each kind are there? Solve using Gauss-Jordan Elimination.

Answer 1

start writing the facts:

p+n+d = 65
n = 2p-4
d = n+13

For elimination, standardize the lines:

p+n+d = 65
-2p+n = -4
-n+d = 13

Now visit

http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

and enter your coefficients, and watch the details emerge.