My Math Forum  

Go Back   My Math Forum > College Math Forum > Linear Algebra

Linear Algebra Linear Algebra Math Forum

LinkBack Thread Tools Display Modes
September 17th, 2014, 03:12 AM   #1
Joined: Sep 2014
From: New York

Posts: 1
Thanks: 0

Systems of Linear Equations - Word Problem involving

Hi Everyone

Can someone please help me out on the following word problem - been trying to solve this for hours and I can't find answer(s) that make sense

A bank teller has a total of 70 bills in five-, ten- and twenty-dollar denominations. The total value of the money is $960.

(a) Find the total number of solutions
(b) Find the solution with the smallest number of five-dollar bills
(c) Find the solution with the largest number of five-dollar bills

FutureNurse26 is offline  
September 17th, 2014, 03:37 AM   #2
Senior Member
Joined: Dec 2013
From: Russia

Posts: 327
Thanks: 108

Let $x$, $y$ and $z$ be the number of five-, ten- and twenty-dollar bills, respectively. Form two equations saying that the total sum is \$960 and the number of bills is 70. Use them to express $x$ and $y$ through $z$. For each $z$, the corresponding values of $x$ and $y$ form a solution of the two equations. You need to observe two restrictions: each of $x$, $y$ and $z$ is an integer and is between 0 and 70. So draw the graphs of $x(z)$ and $y(z)$ and for $0\le z\le 70$ find the interval of $z$ where $0\le x,y\le 70$. The number of integer $z$ in that interval equals the number of solutions.
Evgeny.Makarov is offline  

  My Math Forum > College Math Forum > Linear Algebra

equations, involving, linear, problem, systems, word

Search tags for this page
Click on a term to search for related topics.
Thread Tools
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
Systems of Linear Equations kaspis245 Algebra 9 August 8th, 2014 10:07 AM
Proof about linear systems of equations david940 Linear Algebra 2 July 25th, 2014 06:12 PM
Non-linear systems of equations Akcope Calculus 3 March 14th, 2014 01:49 AM
Help on Systems of linear equations Jake_88 Linear Algebra 1 June 15th, 2010 05:59 AM
Systems of linear equations in two variables maxpalme Algebra 1 April 2nd, 2009 10:33 AM

Copyright © 2019 My Math Forum. All rights reserved.