1. Colegio San Patricio
3rd Period Math Review WITH ANSWERS
School Year 2009 – 2010
Name ___________________________________________________List No._________8th_________
Teacher_________________________________________________ Date_______________________
I. Comparing Ratios
1. You need to buy a bottle of catsup. As you look at the bottles on the shelf, you notice that
you can pay $2.70 for an 18 oz. bottle, or you can pay $1.68 for a 12 oz. bottle. Which bottle is
the better buy?
$2.70/ 18 = $0.15 ¢ $1.68/ 12 = $0.14 ¢
So the 12oz. is the cheapest bottle, and the better buy.
2. In a major city, 8% of the potential work force, which consists of 550,000 people, are
unemployed. How many people are unemployed?
550,000 people - 100% (550,000 * 8)/100 = 44,000
_______ - 80% So 44,000 represent the 8% of unemployed people.
3.) A large university employs 275 work study students. The 150 men that are employed take
home a total of $6,000 per week, and the 125 women earn $5,625 per week. Who, on the
average, makes more, a man or a woman?
Men = $6000/150 = $40 per week
Women = $5625 /125 = $45 per week So women earn $5 more dollars per week.
4.) If you have 3 dogs out of 10 pets, which is the dog’s ratio?
a) 0.7 b) 0.3 c) 0.75 d) 0.45
3/10 = 0.3
II. Central Tendency Measures (Mean, median, mode)
5.) In the following exercises find the mean, median and mode.
a) 6, 7, 12, 14, 12, 11, 10, 12, 9, 10
Mean = (6 + 7 + 12 + 14 + 12 + 11 + 10 + 12 + 9 + 10)/10 = 10.3
Median = 10.5
6, 7, 9, 10, 10, 11, 12, 12, 12, 14 so (10 + 11)/2 = 10.5 is the median.
Mode = 12
b) 10, 12, 12, 14, 20, 16, 12, 14, 11
Mean = 13.4 Median = 12 Mode = 12
c) 4, 8, 3, 4, 9, 7, 8, 3, 2, 4, 3
Mean = 5 Median = 4 Mode = 3 and 4

2. III. Numerical Sequences
6.) What is the rule for the next sequence: 3, 5, 7, 9, …?
The difference between each integer is +2, so the first part of the rule is 2n. Now you do
a quick check just so see if you need to add or subtract so the rule is “complete”.
(Remember n = position of the integer in the sequence.)
2n = 2(1) = 3 (it should give us the first number of the sequence). We notice that we
should add +1 so that statement is correct. Then our rule is complete.
2(1) = 2 +1 = 3. Now we have the rule: 2n + 1.
7.) What is the next number in the following sequence: 1, 4, 7, 10 …?
10 + 3 = 13. (Just in case you want the rule: 3n -2.)
8.) From the following numerical sequence -2, 3, 8, 13, …, what is the number on the
7th.position?
Rule: 5n – 7 when n= 7, we substitute: 5(7) – 7 = 35 – 7 = 28
9.) Being 3n - 5 the rule for a numerical sequence, which is the corresponding number for n
= -4? Rule: 3n – 5 substitute n = -4 3(-4) – 5 = - 12 – 5 = -17
IV. Linear Equations
10.) The Tri-State car rental agency charges a flat fee of $25 plus $0.17 per mile to rent a
subcompact car on weekends. Write a linear model for the cost in terms of the number of
miles driven. How much would you pay if you rented the car for 3 days and you traveled 50
miles each day?
Cost = $25 + $0.17x x = miles used
3 days * 50miles per day = 150 miles
Substitute: Cost = $25 + $0.17(150 miles) = $50.5
11.) What is the solution for the following equation: 5x - 3x + 15 = x + 16?
Simplify first: 2x + 15 = x + 16
Variables on one side: 2x – x = 16 - 15
Simplify: x=1
12.) What is the solution for the following equation: 2(x - 1) = x + 1?
2(x - 1) = x + 1
2x - 2 = x + 1
2x – x = 1 +2
x=3
13.) According to the following chart, which value should be the accumulated one by the
8th.month?
y = b + ax
y = $ 750 + (1) ($50)
y = $ 750 + (2) ($50)
y = $ 750 + (3) ($50)
y=…?
Just substitute:
y= $750 +(8) ($50) = 750 + 400 = $1150

3. 14.) Solve: -2(x + 3) = x + 6
-2x – 6 = x + 6
-2x – x = 6 + 6
-3x = 12
x = 12 / -3 (Remember: it’s INVERSE OPERATION, so the number moves WITH the sign.)
x = -4
V. Graphing Linear Equations
15.) Use a table to graph the equation: 16.) Use x and y intercepts to graph the
2y – 10x = 20 equation: 8y + 4x = 24
x -2 -1 0 1 2
Y 0 5 10 15 20
1. Isolate “y”: * When you read “Quick graph” or “Intercepts”
2y -10x = 20 it means you should let x= 0 and y=0.
2y = 20 + 10x x=0 y=0
y = (20 + 10x)/2 y= 3 x=6
y = 10 + 5x 8y + 4(0) =24 8(0) +4x=24
2. Substitute for EACH “x” value 8y = 24 4x=24
y = 10 + 5(-2) y = 10 + 5(-1) y= 24/8 = 3 x=24/4= 6
= 10 – 10 = 10 -5
=0 =5 * Now you can graph because you have
y = 10 + 5(0) y = 10 + 5(1) 2 coordinates to plot in the
“Cartesian Plane”.
= 10 = 10 + 5 (0, 3) and (6, 0)
= 15
y = 10 + 5(2)
= 10 + 10
= 20
3. Graph

4. Slope of a Line:
17.) Find the slope of the line 18.) Find the slope of the line passing
through points (9, 2) (-5, -2).
m = y2 – y1
X2 – x 1
x1 y1 x2 y2
(9, 2) (-5, -2)
Substitute in the formula:
-2-2 = - 4
-5-9 -14
So the slope is 2
7
Slope = ____-1_______________________ Slope = ___2/7___________________
*Remember: If the line is FALLING it
has a negative slope.
*Choose 2 points that ARE whole numbers.
* Then, just get rise and run.
* Rise= the “height” = 1
* Run= the “length” = 1
So 1/1 =1, and because it’s falling is -1.
19.) Determine whether the line passing through the points (-9, -4) (6, -1) rises, falls, is horizontal
or vertical line.
m = -1 –(-4) = -1+4 = 3 = 1
6 –(-9) 6+9 15 5
So the slope rises.
20.) Find the slope of the line passing through points (3, -2) (5, 5).
m = y 2 – y1
X2 – x1
x1 y1 x2 y2
(3, -2) (5, 5)
Substitute in the formula:
5-(-2) = 5+2 = 7
5–3 2 2
So the slope is 7
2