Gauss-Jordan Elimination Method w/Matrices

HI All,

I need help solving this Gauss-jordan elimation word problem:

I need to define the variables; if necessary or applicable, organize the information given into a chart, and setup a system of equations. Then solve using Gauss-Jordan method.

A minor league baseball park has 7000 seats. Box seats cost$6,grandstand seats cost $4,and bleacher seats cost $2. When all seats are sold, the total revenue is $26,400. If the number of box seats is one-third the number of bleacher seats,how many seats of each type are there?

Thanks for your help

Freedom 100