Question

In 1997, a typical American consumed 52 liters of bottled water, and in 2001, a typical
American consumed 74 liters of bottled water. Let y be the number of liters of bottled water
consumed by a typical American in the year x, where x = 0 represents the year 1997.
(a) Which of the following linear equations could be used to predict the number of liters of
bottled water consumed in a given year x, where x = 0 represents the year 1997? Explain/show
work.

A. y = 22x + 52
B. y = 5.5x + 52
C. y = −5.5x + 74
D. y = 22x − 6


(b) Use the equation from part (a) to estimate the number of liters of bottled water consumed by
a typical American in 2009. Show work.

(c) Fill in the blanks to interpret the slope of the equation: The average rate of change of bottled
water consumed with respect to time is ______________________ per ______________.
(Include units of measurement.)

Answer 1

started at 52, increased 22 in 4 years, or 5.5 per year.

Looks like B to me.

Now use that formula to answer the other parts.