Algebra 2
WS 2.2: Writing Linear Functions
Name ______________________________
Class Period _______________
1. The membership to an online video site is $10 per year and the movie rental rate is $2.95 per
movie. Write an equation that models this situation.
2. The price for a U.S. postage stamp was $0.13 in 1975 and $0.37 in 2005. The price has
increased at a rate that is approximately linear. Write an equation representing this situation
and use it to predict the cost of a stamp in 2015.
3. An airplane’s altitude is 100 feet as it is descending for a landing on a runway whose
touchdown point is 5000 feet away horizontally. Draw an accurate graph and write an equation
to represent the path of the airplane.
4. A local shipping company charges a flat drop fee and an additional $4.50 per pound for
delivering packages within a certain radius. Kelsey paid $16.50 to have a 3 pound package
delivered in the specified area. Write an equation to model the situation and use it to predict
the cost of delivery for a 5 pound package.
5. Plans for a new water slide call for the slide to descend from a platform 80 feet tall. The
slide will drop 1 foot for every 3 feet of horizontal distance. Write an equation to represent
the path of the slide.
a) What horizontal distance do you cover when descending the slide?
b) Find the length of the slide.
6. Rick earns a flat rate per hour plus 5% commission on his total sales each week. Last week, he
worked 10 hours and made $900 in sales. Write an equation to represent his pay and
determine his hourly rate if he earned a total of $115.
7. In a chemistry experiment, you record the temperature of a particular compound to be -5oF
one minute after you begin the experiment. It is expected that the temperature will increase
4.5o per minute while the experiment is being conducted. Write a linear model for this
situation and use it to predict when the temperature of the compound will reach 32oF.
8. In 1980, 3.5% of the doctorates in engineering were awarded to women. By 1990, 8.5% were
earned by women.
a) Find the average rate of change in the percent of engineering doctorates earned by women
from 1980 to 1990.
b) Write a linear model for the number of engineering doctorates earned by women as a
function of time, t, if t = 0 corresponds to 1980.
9. In 1994, the average monthly cost for expanded basic cable television service was $21.62. In
2004, this cost had increased to $38.23.
a) Write a linear model for the cost of cable as a function of time, if t = 0 corresponds to
1990.
b) Using your model, predict the cost in 2010.
10. Ancient cities often rose in elevation through time as citizens built on top of accumulating
rubble and debris. An archaeologist at a site dates artifacts from a depth of 54 feet as 3500
years old and artifacts from a depth of 26 feet as 2600 years old.
a) Write a linear equation that models an artifact’s age as a function of depth.
b) If an artifact is discovered at a depth of 18 feet, approximately how old is it?