
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
May 10th, 2008, 01:05 PM  #1 
Newbie Joined: May 2008 Posts: 1 Thanks: 0  A problem that has me rather stumped.
Phil T. Rich has $100 and spends $3.00 of it per day. Ernest Worker has only $20 but is adding to it at a rate of $5.00 per day. Let x be the number of days that have passed. Write the definition of x. Then write two expressions, one representing how much Phil has after x days and the other representing how much Ernest has after x days. Who has more money , and how much more, after: i. 1 week ii. 2 weeks After how many days will each have the same amount of money? Write and solve an equation to find this number of days. Show that each actually does have the same amount of money after the number of days you calculated in part c. (Work required) I've been looking at this one since yesterday. I am not inclined for mathematics, so this is kind of like trying to read another language. Any help would be GREATLY appreciated. 
May 10th, 2008, 02:13 PM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,370 Thanks: 2007 
Well, x will be the number of days that have passed (since the day when Phil T. Rich has $100). This will apply until x = 33 1/3, since Phil T. Rich can't spend money he doesn't have. After x days, Phil has (100  3x) dollars and Ernest has (20 + 5x) dollars. After 1 week (i.e., 7 days), Phil has $79 and Ernest has $55, so Phil has $24 more than Ernest. After 2 weeks (i.e., 14 days), Phil has $58 and Ernest has $90, so Ernest has $32 more than Phil. After 10 days, each has $70 (since 100  3x = 20 + 5x implies 100  20 = 5x + 3x, i.e., 100 = 8x, i.e., x = 10). Confirmation: $(100  (3 × 10)) = $70 and $(20 + (5 × 10)) = $70. 

Tags 
problem, stumped 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Tricky problem and I'm just stumped  cups  Calculus  2  October 30th, 2012 01:13 PM 
Very Stumped on This Limit Problem  soulrain  Calculus  4  June 4th, 2012 06:58 PM 
stumped  tangosix  Algebra  2  March 2nd, 2010 10:39 AM 
I'm stumped!!  yabo2k  Advanced Statistics  1  October 27th, 2009 05:41 AM 
I'm Stumped  bretttolbert  Algebra  4  April 5th, 2008 12:15 PM 