Cracking The SAT Premium

=   10, which   is  (B).

15. C There are a variety of ways to approach this question. You could solve one equation for s
    or t and substitute it into the other equation, but look to see if you can do it more simply by
    stacking and adding (or subtracting) the equations. If you double the first equation to get 34s

• 40t = 118, you can then stack and subtract the equations to eliminate t and solve for s, as
  follows:

So, 4s  =   8   and therefore   s   =   2.  Now plug    in  2   for the value   of  s   in  one of  the equations:

30(2)   +   40t =   110,    so  40t =   110 –   60, so  40t =   50  and t   =       =   1.25.   Next,   plug    s   =   2   into    the

answer  choices to  determine   which   one matches your    target  of  1.25:   (C),        =

1.25.

16. 
    

    A The best way to approach this question is through POE. Choice (A) states that the majority
    of students polled logged in more times than they posted. The values along the x-axis of the
    graph are, for most of the data points, higher than the values along the y-axis of the graph,
    and thus (A) is true according to the data provided. This same data contradicts (B) and (C).
    You can eliminate (D) because the data does, in fact, allow you to draw a conclusion about
    the relationship between the variables.

    
    


17. 
    

    B Don’t get too thrown off by the graph. All you need to know to solve this question is that

    
    

perpendicular   lines   have    slopes  that    are the negative    reciprocals of  each    other.  Since   the

standard    equation    for a   line    is  y   =   mx  +   b,  the slope   of  the f(x)    line    is  3.  The slope   of  the

h(x)    line    must    therefore   be  – . The only    answer  choice  that    matches is  (B).

18. C The best way to deal with this question is to Plug in the Answers (PITA), starting with (A).

If  x   =   6,  then    y   =   3^6     =   729.    This    is  less    than    4,000,  so  eliminate   (A) and move    to  the next

answer  choice. If  x   =   7,  then    y   =   3^7     =   2,187.  This    is  still   less    than    4,000,  so  eliminate   (B).    If

x   =   8,  then    y   =   3^8     =   6,561.  This    is  greater than    4,000,  so  (C) must    be  the correct answer.

19. D The first step here is to simplify the equation and solve for a. Start by multiplying both

sides   by  16  to  get 16a =   4a^2 .  Divide  both    sides   by  4   to  get 4a  =   a^2 .   Divide  both    sides   by  a

to  get 4   =   a.  This    is  now your    target  answer. Plug    a   =   4   into    the values  of  a   in  the answer