Solving Linear Equations Word Problems

Section 3.1 # 94
Demand equation. Helen's Health Foods usually sells 400 cans of ProPac Muscle Punch per week when the price is $5.00 per can. After experimenting with the prices for some time. Helen has determined that the weekly demand can be found by using the equation
D=600-40p,
Where d is the number of cans and p is the price per can.

a) Will Helen sell more or less Muscle Punch if she raises her price from $5.00?

b) What happens to her sales every time she raises her price by $1.00

c) Graph the equation

Section 3.2 #62
Retirement pay. The annual Social Security benefit of a retiree depends on the age at the time of retirement. The accompanying graph gives the annual benefit for persons retiring at ages 62 through 70 in the year 2005 or later (Social Security Administration, www.ssa.gov). What is the annual benefit for a person that retires at the age of 64? At which retirement age does a person receive an annual benefit of 11,600? Find the Slope of each line segment on the graph, and interpret your results. Why do people who postpone retirement until 70 years of age get the highest benefit.

(62, 7000) (64, 8000) (67, 10000) (70, 12400)

Section 3.3 #10
Write an equation. Use slope-intercept form if possible.

Section 3.4#78
Direct Deposit. The percentage of workers receiving direct deposit of their paychecks went from 32% in 1994 to 60% in 2004 (www.directdeposit.com). Let 1994 be year 0 and 2004 be year 10.
A) Write the equation of the line through (0,32) and(10,60) to model the growth of direct deposit.
B) Use the graph to predict the year in which 100%of all workers will receive direct deposit of their paychecks.
C) Use the equation from part(a) to predict the year in which 100%of all workerswill receive direct deposit.

Section 3.5#46
Christmas tree. The price of a Christmas tree varies directly with the height. If a 5 foot tree costs $20, then what is the price of a six foot tree?

See attached file for full problem description.