Thursday, December 15, 2011

How do you solve this break point even question using algebraic expressions?

You have $22 in your bank account and deposit $11.50 each week. At the same time your cousin has $218 but is withdrawing $13 each week .





a. When will your accounts have the same balance?


b. How much money will each of you have after 12 weeks





Please provide a detailed explanation on how to solve this problem step by step without using graphs.|||For the first part, create two expressions for the two people. You start off with 22, and 11.5 is added every week. Therefore at any point, you have 22 + 11.5n in your account, where n is equal to the number of weeks that have passed. Similarly, your cousin has 218 - 13n at any point.





To work out when you have the same amount, you just have to equate the two expressions, giving


22 + 11.5n = 218 - 13n Group like terms to give 24.5n = 196 and solve to give n = 8.





22 + 11.5*8 = 114 = 218 - 13*8





For the second part, you just have to make n=12 and then plug it into both expressions


(22 + 11.5*12 and 218 - 13*12 respectively)

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