Problema Solution
In 1985, the U.S Postal Service charged $0.22 for first class letters and cards up to 1 oz. By 2009, the price had increased to $0.44 Let x represent the year, and y represent the cost for 1 oz of first class postage. Find the average rate of change of the cost per year and interpret the answers.
Answer provided by our tutors
(1985,0.22), (2009,0.44) are two points.
Average rate of chnage =(0.44-0.22)/(2009-1985).
=0.22/24.
=0.01.
It intererets cost in dollors per year.
It tells us cost required for change of service charges per year.