Cracking The SAT Premium

choices to  determine   which   one matches 4.  Choice  (D) is  the answer, since   2   =   2   =

2(2)    =   4.

20. 
    

    B Since work = rate × time, the 280 in the equation must represent the total number of meals
    (i.e., the “work”). All three chefs are working together, so they work for the same amount of
    time, and x must represent that time. The coefficients 8, 4, and 2 must therefore represent
    the chefs’ respective rates, or how many meals each prepares in a set amount of time. Since
    8 is the greatest of these three coefficients, 8x must be the meal output of the fastest chef,
    either (B) or (C). Now you need to solve the equation: 8x + 4x + 2x = 280. Combining like
    terms gives you 14x = 280. Divide both sides by 14 to determine that x = 20. This number
    represents the amount of time that the chefs worked, so the actual number of meals prepared
    by the fastest chef would be 8 × 20 = 160 meals, which is (B).

    
    


21. 
    

    D Start by finding the slope of the line provided on the graph using the points (0, –4) and (6,

    
    

0)  and the point-slope formula:     .  When    this    line    is  reflected

across  the line    y   =   x,  the x   and y   values  switch, so  the new slope   would   be  the reciprocal  of

the original    slope.  Since   our original    slope   was  ,  our new slope   will    be   .  The numerator

here    reflects    the gain    or  loss    of  pieces  of  fruit   in  the harvest,    and the denominator reflects

the nutrients   subtracted  or  added.  This    means   that    for every   two nutrients   added,  there   will

be  a   harvest gain    of  three   pieces  of  fruit,  which   is  (D).

22. 
    

    D The issue that needs clarification here is whether the students polled by Joe thought that a
    score of 1 or a score of 5 was good. Since (A) and (C) deal with George’s poll, they would
    do nothing to help clarify this ambiguity. Choice (B) might help us to figure out which of the
    students Joe polled were interested in the Model UN Club; it would not help to determine
    whether 1 or 5 was the best rating. Choice (D) is correct.

    
    


23. 
    

    C In order to determine the normal cost for renting skis and snowboards, you need to write
    two equations and then manipulate and solve those equations. If you call skis x and
    snowboards y, your two equations will be 5x + 2y = 370 and 3x + 4y = 390. Look for a
    way to stack and add the equations to eliminate one of the variables. For instance, multiply
    the first equation by 2 to get 10x + 4y = 740, and then stack and subtract the equations, as
    follows:

    
    

So, 7x  =   350 and x   =   50, so  the price   of  a   pair    of  skis    is  $50.    Plug    this    number  back    into