Arsenic Removal From Drinking Water (Group Project)

Author David Graser, Yavapai College, Prescott, AZ (


This project is a modification of the Arsenic Removal from Drinking Water to allow students to work together in groups.

  • Content Area – College Algebra, Finite Math
  • Time Frame – 2 to 3 weeks with mini-lectures
  • Published – June 22, 2015
  • Keywords – system of linear equations, matrices, row echelon form, systems with an infinite number of solutions

Project Content

Project Letter (DOC | PDF)

Project Background (PDF)

Scaffolding Resources

Technology Assignment: Write Out Equations (PDF)
This PDF handout lays out a strategy for finding the system of equations for theproject.

Once studentshave written out the system of equations, theywill use ashared document in Google Drive to demonstrate theirwork. Each member of theirteam should use a different contamination level for Well 3 in completing this assignment as well asthe other two technology assignments.

The video below shows how theywill use Google Apps to document and share the equations you come up with.

Since theyare using a shared document, all members of theirteam can see and comment on what theyare doing.

Upon completing this assignment, theyhave a system of equations describing the amounts of water pumped from the wells described in the projectletter.

What is Parts per Million or Parts per Billion? (PDF)

Technology Assignment: Row Operations

In this technology assignment studentscarry out the row operations on theirsystem of equations.

Theycarry out the row operations on theirsystem by hand. Once theyhave found the row operations, theyput them into a shared Google Doc. The steps for solving the system of equations are shown in the video below. This video describes a slightly different problem.

Once theyhave completed this assignment, theyshould have a solution to the system of equations. It may not be exactly what theywere expecting. Theywill verify that the steps are correct in the next tech assignment.

Technology Assignment: Row Operations in Google Sheets

The goal of this assignment is to carry out the row operations for the project in Sheets. Hopefully, this will verify the work theyhave already done in earlier technology assignments. They take their system of equations and watch the video below to learn how to do row operations in Google Sheets. Theyuse the shared spreadsheet to do this so each of theirteam members can see what theyhave done.

The row operations you do in Google Sheets should yield the same matrices as the row operations you did by hand.

Theymay have some trouble interpreting the final matrix. To help themsee how to interpret this matrix, have them take a look at a similar problem in this handout.

Dependent Systems Handout (PDF)


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