1. SWBAT…write algebraic equations from data
Tues, 11/5/10
Agenda
WU (10 min)
Writing algebraic equations from data (30 min)
Warm Up:
Any questions on the practice problems on the back of this week’s agenda?
HW#3: Algebraic Rules

2. The table shows the cost C of renting a boat for h hours.
Which equation best represents the data?
1.) C = 7.25h 3.) C = – 7.25h
2.) C = h ) 7.25h
Hours 1 2 3
Cost ($)
7.25
14.5
21.75

3. The table shows the total amount of rain during a storm
The table shows the total amount of rain during a storm. Write a formula to find out how much rain will fall after a given hour.
1.) h = 0.45n 2.) n = 0.45h
3.) h = ) h = 1.8n
Hour (h) 1 2 3 4
Inches (n)
0.45
0.9
1.35
1.8

4. The table shows the labor charges of an electrician for jobs of different lengths.
Which function represents the situation?
1.) C(n) = 25n ) C(n) = 25n + 30
3.) C(n) = 35n ) C(n) =

5. A company sells candy bars
A company sells candy bars. The table below shows the total weight of a box with 1, 2, 3, and 4 candy bars.
Number of candy bars in box
Total weight in (ounces) 1
9.5 2
15.5 3
21.5 4
27.5
a.) T = 6c + 3.5
b.) T = Total weight of the box, including its content in ounces
3.5 = the initial weight of the box without any candy in it, in ounces
6 = the weight of the candy bar that we add to the box, in ounces
c = the number of candy bars in the box
Write an algebraic rule that can be used to determine the total weight of the box for any number of candy bars. Show or explain your work.
Describe what each number and variable represents in your algebraic rule.

6. Exit Slip (to be collected and graded)
The total cost for a plumbing job is determined by a one-time fee of $145 plus $65 per hour worked plus the cost of parts.
Write an algebraic rule that can be used to determine the total cost.
Describe what each number and variable represents in your algebraic rule.
a.) T = h + p
b.) T = Total cost for a plumbing job, in dollars
145 = the one-time fee, in dollars
h = the number of hours worked
65 = the amount of money paid to the worker
p = the cost of parts

7. A growing T-pattern made of small square tiles is shown below.
Figure Figure Figure 3
Write an algebraic rule for the total number of tiles, T, in terms of the figure, n.
T = 3n + 2

8. A construction company sells tiles in one size
A construction company sells tiles in one size. The table below shows the perimeter when one, two, three and four tiles are fit together.
Number of tiles (t)
Picture of tile
Perimeter of tile (P) 1 4 2 6 3 8 10
P = 2t + 2
P = 2(8) + 2
P = 18
Write an algebraic rule for the perimeter.
b. Using this table, what would you predict is the perimeter of a border with eight tiles?