SAT Mc Graw Hill 2011

690 MCGRAW-HILL’S SAT

8.A You are told that: 12 v= 3 w
Divide by 3: 4 v=w
Multiply by 2: 8 v= 2 w
The question asks for the value of: 2w− 8 v
Substitute for 2w: 8 v− 8 v= 0
Alternatively, you can try finding values for vand w
that work, like 1 and 4, and plug them into 2w− 8 v
and into the choices and find the match.
(Chapter 8, Lesson 1: Solving Equations)

9.C 2 x+1 > 5
Subtract 1: 2 x> 4
Divide by 2: x > 2
Interpret the absolute value:x> 2 OR x< − 2
You are told that xis negative, so x< −2 is the answer.
(Chapter 8, Lesson 6: Inequalities, Absolute Values,
and Plugging In)

10.B −x^2 − 8 x− 5
Substitute −2 for x:−(−2)^2 −8(−2) − 5
Square −2: −(4) −8(−2) − 5
Simplify: − 4 + 16 − 5 = 7
When evaluating −x^2 , don’t forget to square the value
beforetaking its opposite!
(Chapter 8, Lesson 1: Solving Equations)

11.D

Cross-multiply: 15 ≤ 2 m
Divide by 2: 7.5 ≤m
Since mis greater than or equal to7.5, (D) is the answer.
(Chapter 8, Lesson 6: Inequalities, Absolute Values,
and Plugging In)

12.B First find the price after the 6% sales tax:
$60.00 ×.06 =$3.60 tax
$60.00 +$3.60 =$63.60 price with tax
(A simpler way is just to multiply 60 by 1.06.)
Now find how much change Theo received:
$70.00 −$63.60 =$6.40 change
(Chapter 7, Lesson 5: Percents)

13.A Write an equation for the first sentence.
n−m=r
Because none of the answer choices contain m,solve
for min terms of rand n: n−m=r
Add m: n=r+m
Subtract r: n−r=m
Now write an expression for what the question asks for:
s+ 2 m
Substitute for m: s+2(n−r)
Distribute: s+ 2 n− 2 r
Alternatively, you can substitute numbers for n, m,
and r,making sure they “work,” and get a numerical
answer to the question.
(Chapter 8, Lesson 1: Solving Equations)

52

m 3

≤

14.D Two points on line lare (0, 0) and (10, y).

Find the slope of the line:

Cross-multiply: 5 y= 30

Divide by 5: y= 6

Since y=6, the height of the triangle is 6. Find the area:

A=^1 ⁄ 2 (base)(height)

Substitute 48 for A: 48 =^1 ⁄ 2 (base)(6)

Simplify: 48 =3(base)

Divide by 3: 16 =base =x

Now find x+y= 16 + 6 =22.

(Chapter 10, Lesson 4: Coordinate Geometry)

15.A Ellen travels the first 15 miles at 30 miles per

hour. Find out how much time that takes:

d=(rate)(time)

Plug in known values: 15 = 30 t

Divide by 30:^1 ⁄ 2 hour =t

The rest of the trip, which is (y−15) miles long, she

travels at an average speed of 40 miles per hour:

d=(rate)(time)

Plug in known values: (y−15) = 40 t

Divide by 40:

Add the two values together to find the total time:

(Chapter 9, Lesson 4: Rate Problems)

16.B Set up the relationship in equation form:

Plug in what you’re given:

Simplify: 8 = 16 k

Divide by 16:^1 ⁄ 2 =k

Write the new equation:

Plug in new values:

(Chapter 11, Lesson 4: Variation)

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==

1

2

8

4

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16

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y
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n

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+

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