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

12 Practice Tests for t h e SAT I
Practice Test Four Answers and Explanations
383
T h is is t h e sma ll est num b er. T h e median wi ll b e x + 2,
or 100.
13. 4
Difficulty: Medium
Strategic Advice: Use t h e grap h to find t h e va l ue of h (x),
t h en use t h ey-coordinate in your k function.
Getting to the Answer:
k (-2) = h ( - }) + 3 = h (-1) + 3 = 1 + 3 = 4
( h (-1) = 1 came from t h e point (-1, 1) on t h e grap h )
14. 120
Difficulty: Hig h
Strategic Advice: How many c oices does first friend h ave?
T h en h ow many ponies does t h at l eave for t h e second friend?
Getting to the Answer:
T h e first friend h as h is or h er c h oice of 5 ponies, w h ic h
l eaves 4 for t h e secon d friend, 3 for t h e t h ird friend, 2 for
t h e fourt h friend, and t h e l ast one is stuck wit h t h e l ast pony.
So t h e num b er of possi b i l ities is
5 x 4 x 3 x 2 x 1 = 120
15. 50
Difficulty: Medium
Strategic Advice: Try to find t h e ot h er ang l es of ti.ABC.
Getting to the Answer:
Since MBC is isosce l es, ang l e B is a l so 50°, and ang l e ACB
is 180° - 50° - 50° = 80°.
ACD is a l ine, so
80° + x + x = 1 80°
80° + 2x = 1 80°
2x= 100°
x=50°
16. 3
4
or 1.33
Difficulty: Medium
Strategic Advice: Eva l uate eac h side of t h e equation b y
p l ugging into t h e definitions, t h en so l ve for a.
Getting to the Answer:
::::} (3a) 2(4) 3(3a) 8 + 9a
4 ¢= (3a) = 3( 4) + 2(3a) = 12 + 6a
Since t h ese are equa l , 8 + 9a = 12 + 6a
9a=4 + 6a
1
17. 2
or .5
3a=4 4 a=-3
Difficulty: Hig h
Strategic Advice: Find t h e possi b l e va l ues of s an d d , t h en
determine w h ic h wi ll give you t h e l argest s l ope t h roug
t h e two points. Notice t h atx and y are not in t h eir usua h
positions in t h e equation.
l
Getting to the Answer:
First, p l ug (5, s) into t h e equation of t h e function:
5=2s + 3
2=2s 2
1 =5 2
s= 1,- 1
Now do t h e same wit h ( 11, d) :
11=2 d2 +3
8=2 d2
4= d2 d =2,-2 d -s d -s
T h e s l ope t h roug h (5,s) and (11, d) is TT-=s =-6-. To
make this as large as possible, choose d = 2, s = -1 so that
t h e s l ope dis t h is: -s 2- (-1)
6 6 = _3_
6 =2 1
18. 30
Difficulty: Hig h
Strategic Advice: Write out a c h art wit h rate, time, and
distance and fi ll in w h at you know. T en try to use t h at to
so l ve for t h e distance. If it took h er t h ours to get to t h e
circus, and t h e tota l trip was 2.2 h ours, h ow l ong (in terms
oft) did s h e spend returning?
Getting to the Answer:
2 h ours and 12 min= 2 + = 2.2 h ours
rate time distance
To circus 30 mp
From circus 25 mp h t
2.2-t d
Now use t h e rate formu l a r x t = d for b ot h parts of t h e trip:
30 Xt= d
25 x (2.2-t) = d