3.4 Problem Solving Answers

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Problem #3

a) Create a verbal model for the following and then b) develop the algebraic equation:

Currently, you have $60 and your sister has $135.  You decide to save $5 of your allowance each week, whereas your sister decides to spend her whole allowance plus $10 each week.  How long will it be before you have as much money as your sister?

Money you currently have + Money you save each week . Time
(# of weeks)		 = Money sister currently has - Extra money she spends each week . Time
(# of weeks)

60 + 5x = 135 -10x

Problem #4

a) Create a verbal model for the following and then b) develop the algebraic equation:

Suppose you live in Greenville, SC, where the temperature is 69 degrees and going up at a rate of 2 degrees an hour.  You are talking on the phone to your friend who lives in Waterloo, IA, where the temperature is 84 degrees and going down at a rate of 3 degrees an hour.  If the temperatures continue to change at the same rates, how long would you and your friend have to talk before they would be equal?

Greenville temperature + Rate of temperature increase . Time
(# hours)		 = Waterloo temperature - Rate of temperature decrease . Time
(# of hours)

69 + 2x = 84 -3x

 

 

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