SOLUTION: Justin has already saved $40 and wants to buy a playstation 2 for $129 about four months from now. To find how much he should save each week between now and then, he wrote 40+16x=1

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Question 158932: Justin has already saved $40 and wants to buy a playstation 2 for $129 about four months from now. To find how much he should save each week between now and then, he wrote 40+16x=129. Explain this equation.
Found 2 solutions by KnightOwlTutor, checkley77:
Answer by KnightOwlTutor(293) (Show Source):
You can put this solution on YOUR website!
This is an example of a linear equation y= mx + b
He started of with a specific amount of $40- this is b the constant value.This $40 is going to be used for the purchase. We know the value of y which is the total cost of the playstation 2= $129. We know that he plans to make the purchase in 4 months which is equivalent to 16 weeks.Each month contains 4 weeks. In this equation it represents the slope of the line-m. X= to the amount of money that he needs to save each week. Therefore, we can solve this problem:
$129-40=16x $5.57 is approximate the amount of money he needs to save per week.

Answer by checkley77(12844) (Show Source):
You can put this solution on YOUR website!
40+4*4.2x=129 there are 4.2 weeks per month.
40+16.8x=129
16.8x=129-40
16.8x=89
x=89/16.8
x=$5.30 per week is the necessary savings.