SOLUTION: Amber is signing up for cell phone service. She is trying to decide between Plan A, which costs $54.99 a month with a free phone included, and Plan B, which costs $49.99 a month,

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: Amber is signing up for cell phone service. She is trying to decide between Plan A, which costs $54.99 a month with a free phone included, and Plan B, which costs $49.99 a month,       Log On


   

Question 153449This question is from textbook Algebra For College Students
: Amber is signing up for cell phone service. She is trying to decide between Plan A, which costs $54.99 a month with a free phone included, and Plan B, which costs $49.99 a month, but would require her to buy a phone for $129. Under either plan, Amber does not expect to go over the included number of monthly minutes. After how many months would Plan B be a better deal? This question is from textbook Algebra For College Students

Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
planA=%2854.99%2Fmonth%29%2BfreePHONE
planB=%2849.99%2Fmonth%29%2B129%28PHONE%29
Let's equate the 2 plans times no. of months "x" for each plan:
planA%28x%29=PLanB%28x%29
%2854.99%2Fmonth%29%28x%29=%2849.99%2Fmonth%29%28x%29%2B129
%2854.99%2Fmonth%29%28x%29-%2849.99%2Fmonth%29%28x%29=129
x%28%2854.99-49.99%29%2Fmonth%29=129 ------------> x%2A%28%285%29%2Fmonth%29=129
x%2Across%285%29%2Fmonth%28cross%285%29%29=cross%28129%2925.8%2Fcross%285%29 , cross multiply:
x=25.8months
Let's try usage of 25months for each plan:
planA:
%2854.99%2Fcross%28month%29%29%2825cross%28months%29%29=1374.75
planB:
%2849.99%2Fcross%28month%29%29%2825cross%28months%29%29%2B129=1378.75
IN 25 MONTHS, PLAN A STILL A BETTER CHOICE
Let's try 26 months:
plan A:
%2854.99%2Fcross%28month%29%29%2826cross%28months%29%29=1429.74
plan B:
%2849.99%2Fcross%28month%29%29%2826cross%28months%29%29%2B129=1428.74
THERE YOU GO, YOU START SAVINGS IN CHOOSING PLAN B WHEN YOU REACH 26 MONTHS OF USAGE. TRY 36 MONTHS? 48 MONTHS?
Thank you,
Jojo