An online retail company tracked total number of purchases monthly. In March 200
ID: 3199839 • Letter: A
Question
An online retail company tracked total number of purchases monthly. In March 2007 they were 4,620 purchases and in February 2008 there were 4,180. The purchases followed a linear model of the form p = S ( t ) = r t + i p=S(t)=rt+i where p p purchases is in 1000's and t t is months where January 2007=0 A. Sales are at a constant rate of - pick the correct units B. Write out the linear model function with the parameter values `p=S(t)= Now answer the following questions using this model C. What does the model predict total purchases will be in August 2010? D. In what month and year does the model predict sales will be 2,420?
Explanation / Answer
(0,4620),(11,4180)
Slope , r= (4180-4620)/(11-0) =-440/11=-40
So the required equation is
S(t) = -40 t + 4620
August 2010 means number of months=41
S(t) =-40(41) +4620 =2980
2420 = -4t+4620
-40t =-2200
t= 55 months
That is 4 years 7 months from March 2007 that is in October 2011