12.Practice.Tests.for.the.SAT_2015-2016_1128p

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12 Practice Tests for t h e SAT
Practice Test Four Answers and Explanations
8. D
Difficulty: Low
Strategic Advice: Use t h e answers given to figure out h ow
muc h was earned in eac h quarter.
Getting to the Answer:
Start wit h (C):
Tota l profits= $63 mi ll ion
First quarter: t(63) = $9 mi ll ion
Second quarter: f C63) = $21 mi ll ion
T h ird quarter: 1(63) = $31.5 mi ll ion
T is l eaves $63m -$9m- $21 m -$31.Sm = $1 .5 mi ll ion,
w h ich is not $2 mi ll ion. The number we came up with is
way too l ow, so move to (D) and repeat t h e same process.
Tota l profits= $84 mi ll ion
First quarter: t(84) = $12 mi ll ion
Second quarter: t (84) = $28 mi ll ion
T h ird quarter: 1(84) = $42 mi ll ion
T h is l eaves $84m -$12m -$28m-$42m = $2 mi ll ion.
9. c
Difficulty: Medium
Strategic Advice: Don't reac h for t h at ca l cu l ator just yet! A
t h at typing mig h t waste va l uabl ll
e time. Rewrite t h e equation
so t h at bot h sides h ave t h e same base number. Once you
get bot h sides in t h e form of a common base, you can set
t h e exponents equa l to eac h ot h er.
Getting to the Answer:
64=43
4 4x + 6 = 542 x = ( 43)2x = 46x
4x+6=6x
6=2x
X=3
A l ternative l y, you cou ld try p l ugging in t h e answers, since
your ca l cu l ator can h andl e t h ese powers. For examp l e,
64 2(1) = 64 2 = 4,096, so (A) is incorrect.
in (A), 4 4x + 5 = 4 4 (l ) +6= 410 = 1,048,576, w h i l e
10. B
Difficulty: Medium
Strategic Advice: Carefu ll y trans l ate to an equation; don't
forget t h at "3 l ess t h an 5" means 5 - 3, not 3 - 5.
Getting to the Answer:
3x+5=x-3
2x+ 5 =-3
2x=-8
X=-4
11. c
Difficulty: Medium
Strategic Advice: T h e circumference of t h e s h aded region
is made up of t h e sum of t h e circumference of t h e bigger
circ l e and t h e circumference of t h e sma ll er circ l e.
Getting to the Answer:
Area= 251t = w 2
r=5
Circumference ( l arger circ l e) = 2w = 27t(5) = 107t
Radius (sma ll er circ l e) = 1radius ( l arger circ l e) = i
Circumference (sma ll er circ l e) = 2w = 21t(-i) = 57t
Tota l circumference of t h e s h aded region= l 07t + 57t = l 57t
12. c
Difficulty: Medium
Strategic Advice: If t h e points are on a l ine, t h at means t h e
s l ope between any two points must a l ways be t h e same.
Write t h e s l ope using two sets of points, t h en set one s l ope
equation equa l to t h e ot h er.
A l so, notice t h is is a great probl em for Pic king Numbers.
Picking somet h ing l ike zero for a makes finding t h e s l ope,
as we ll as so l ving for
2
b -a, very easy.
Getting to the Answer:
S l ope = b - a = l 8 - b
2-1 4-2
2
2
b -a=l8- b
b -a=9- f2_
2- b -a=9
2