SOLUTION: The following table shows worldwide sales of a certain type of cell phone and their average wholesale prices in 2009 and 2010. Quarter Q1 2009 Q1 2010 Wholesal

Algebra ->  Linear-equations -> SOLUTION: The following table shows worldwide sales of a certain type of cell phone and their average wholesale prices in 2009 and 2010. Quarter Q1 2009 Q1 2010 Wholesal      Log On


   



Question 785319: The following table shows worldwide sales of a certain type of cell phone and their average wholesale prices in 2009 and 2010.
Quarter Q1 2009 Q1 2010
Wholesale Price ($) 163 153
Sales (millions) 175 214
(a) Use the data to obtain a linear demand function for cell phones.
q(p) =
Use your demand equation to predict sales to the nearest million phones if the price was set at $156. (Round your answer to the nearest million phones.)

(b) Fill in the blank.
For every $1 increase in price, sales of cell phones decrease by

Answer by xinxin(76) About Me  (Show Source):
You can put this solution on YOUR website!
a)Let the function be Q(P)=aP+b, then
Solved by pluggable solver: Linear System solver (using determinant)
Solve:
+system%28+%0D%0A++++163%5Ca+%2B+1%5Cb+=+175%2C%0D%0A++++153%5Ca+%2B+1%5Cb+=+214+%29%0D%0A++

Any system of equations:


has solution

or



(a=-3.9, b=810.7}

Q(P)=-3.9P+810.7
When P=156, Q(P)=202.3=202 millions
b)-3.9P+810.7-(-3.9*(P+1)+810.7)=3.9 millions=3900000
.....sales of cell phones decrease by 3900000.