Objective 17
Word Problems: Evaluate algebraic expressions
©2002 by R. Villar
All Rights Reserved
Word Problems: Evaluate algebraic expressions
Recall that evaluate means to substitute constants (numbers) for
the variables and solve. For this objective, you will be evaluating
algebraic expressions within word problems.
Example: The cost of a school banquet is $65 + 12n, where n is the
number of people attending. What is the cost for 62 people?
Substitute 62 in place of n in the expression…
65 + 12(62)
= 65 + 744
= $ 809
Example: An employee who receives a weekly salary of $250 and a
5% commission is paid according to the formula p = 0.05s + 250,
where p represents the total amount earned weekly and s represents
the total weekly sales. Find the earnings for a week with $2529 total
sales.
Substitute 2529 in place of the variable that represents total sales
in the expression…
p = 0.05(2529) + 250
= 126.45 + 250
= $376.45
Example: Imagine that you own your own T-shirt business. The cost
of making the designs and buying the T-shirts is $475. In addition to
these one time charges, the cost of printing each T-shirt is $1.75. The
average cost per T-shirt for the business to manufacture x
1.75x  475
T-shirts is modeled by A 
. Find the average cost
x
per T-shirt when x = 100.
Substitute 100 in place of each x in the expression…
A = 1.75(100) + 475
100
= 175 + 475
100
=
650
100
= $6.50