#1 - Toilet Paper Shortage (Systems of Linear Equations)

Solution Video Here

Quarantine Question Number 1: Toilet Paper Shortage

 

1. Bob and Sally have both stockpiled toilet paper for the quarantine.  Bob's family has 30 rolls on hand, and 1 roll lasts his family 3 days.  Sally has 20 rolls on hand, and her family is smaller - 1 roll lasts 5 days.

A.  After how many days will both Bob's and Sally's TP run out?

B.  After how many days will they have the same number of rolls of TP on hand?  How many rolls will that be?


Alternate Method

2.  After their TP runs out, Bob and Sally have to go see John.  John has a garage full of toilet paper and offers his bathroom and use of his TP for a cost.  You have two options:
             -Option 1: $20 per week membership fee and $2 per bathroom visit
             -Option 2:  $10 per week and $3 per bathroom visit.

A. Which is the better deal if you typically only need a bathroom 5 times per week?

B.  Which is the better deal if you typically need a bathroom 15 times per week?

C.  After how many bathroom visits would the cost be the same for each plan?

D.  Bob expects to use the bathroom 12 times per week.  Which plan should he choose?

 

This problem is a challenge for 6th grade,

7th graders should be able to solve by graphing, challenge yourself to learn the other methods.
8th grade should be able to solve these problems using graphing, substitution, and elimination.  Try all 3!

Entry level:  try solving these using graphing.

Video on solving systems of Equations using Graphing

  practice problems and solutions - systems of equations by graphing

Algebra 1 level solution:

  Video lesson: Solving systems of equations with substitution

 

 

  Solving systems of equations with substitution, practice problems and solutions

  Video Lesson: Solving systes of equations with elimination

 

  Solving systems of equations with elimination, practice problems and solutions