Tài liệu Master the Gre 2010 - Part 46 pptx

segments remain ahead. Since the
boat’s average speed is the same
before and after buoy 10, it takes the
boat 5 3 5 = 25 minutes to travel
from buoy 10 to buoy 15.
10. The correct answer is (A). Given n
= 2, the 25th term of SetR=25n +
25 = 25(2) + 25 = 75. Given n = 2, the
24th term of Set S = n +23=2+23
= 25, and two times that 24th term is
50.
11. The correct answer is (C). There’s
no need to calculate either quantity,
and you can cancel the product st
from both columns. To make the
comparison, observe the place-value
shifts from the decimal number 9.3.
In Column A, the decimal point
shifts 3 places left (9,300) and 3
places right (.0093), so the quantity
is equivalent to (9.3)(9.3). You can
now see that Quantity B, which is
(9.3)(9.3), is the same as Quantity A.
12. The correct answer is (B). There’s
no need to calculate either quantity.
Given an area of 12,000 square feet,
the shortest possible rectangular
perimeter is achieved with a square,
in which all sides are the same
length. Column B describes a corral
with a width of 300 feet and a length

of 400 feet. This corral would require
more fence posts than a square
corral.
13. The correct answer is 51.25.
Think of Cynthia’s average rate as
the average of eight equally
weighted one-hour trips. Seven of
those trips receive a weight of 50,
and one of the trips receives a weight
of 60. You can express this algebra-
ically as follows:
750 60
8
350 60
8
410
8
51 25
()
.
+
=
+
==
Cynthia’s average rate during the
entire trip was 51.25 mph. (There’s
no need to round either up or down
to the nearest hundredth.)
14. The correct answer is (D). Sep-
tember and October each saw pre-

cipitous declines in the price of
BioFirm stock and CompuWin stock,
but only a modest increase in the
price of Ardent stock. During each of
these two months, the aggregate
change was clearly negative. In July,
however, a substantial price increase
in CompuWin stock more than offset
the combined decrease in the price of
the other two stocks.
15. The correct answer is (E). The
investor paid about $800 for 40
shares of Ardent stock (priced at
about $20 per share), and then sold
those 40 shares for about $2,200
(priced at about $55 per share).
Accordingly, the investor’s profit
amounted to approximately $1,400.
16. The correct answer is (B). The
area of any triangle =
1
2
3 base 3
height. Using 7 kilometers as the
base of the triangle in this problem,
the triangle’s height is the north-
south (vertical) distance from A to an
imaginary line extending west from
B. Given that farmhouse A is located
a total of 10 kilometers farther west

than farmhouse C, the extension is 3
kilometers long. The triangle’s
height is 4 kilometers (3
2
+4
2
=5
2
,
by the Pythagorean theorem).
Accordingly, the area of triangle ABC
=
1
2
3 7 3 4=14km
2
.
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Practice Test 2 433
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17. The correct answer is (B). You can
make the comparison quickly by rec-
ognizing that Quantity A is the “dif-
ference of two squares” (x
2
2 y
2

)in
the factored form (x+y)(x 2 y),
where y = 2. Or, you can multiply the
two binomials in Column A, and then
simplify: (x +2)(x 2 2) = x
2
+2x 2 2x
2 4=x
2
2 4. Since x
2
2 4 , x
2
2 2,
Quantity A , Quantity B.
18. The correct answer is (A). K
percent is based on $100. Therefore,
K percent = K dollars, and Quantity
B will always be $1 less than
Quantity A.
19. The correct answer is (A). Apply
the formula for determining arith-
metic mean (called AM below), or
simple average. Letting x equal the
other number, solve for x:
AM
Q
PQ
Q
PQ Q

PQ Q
=
+
=
+
=+
−=
x
x
x
x
2
2
2
2
20. The correct answer is (D). Letting
x equal the number of ounces of soy
sauce added to the mixture, 18 + x
equals the total amount of the
mixture after the soy sauce is added.
The amount of peanut sauce (5.76
ounces) must equal 12% of the new
total amount of the mixture, which is
18 + x. You can express this as an
algebraic equation and solve for x:
5.76 5 0.12~x +18!
576 5 12~x +18!
576 5 12x + 216
360 5 12x
30 5 x

30 ounces of soy sauce must be added
to achieve a mixture that includes
12% peanut sauce.
21. The correct answer is (C). x + y +
the measure of the third interior
angle (let’s call it w) = 180. Also, w +
z = 180 (because their angles
combine to form a straight line). So,
you have two equations:
x + y + w = 180 or x + y = 180 2 w
w + z = 180 or z = 180 2 w
Therefore, x + y = z (Quantity A =
Quantity B).
22. The correct answer is (D). The
centered information establishes
that Quantity B, pq, must be
negative, because the product of a
positive number and a negative
number is always negative. As for
Quantity A, try substituting some
simple numbers for p and q.Ifp =1
and q = 21, then p +
q = 0 while pq =
21, and therefore p + q . pq. But if p
=
1
4
and q = 2
1
2

, p + q = 2
1
4
while pq
=
1
8
, and therefore p + q , pq. Thus,
which quantity is greater depends on
the values of p and q.
23. The correct answer is (B). The
range of D = 10 2 3 = 7. The median
of D = the arithmetic mean of 6 and 9
(the two middle terms) = 7.5.
PART VI: Five Practice Tests434
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24. The correct answer is (B). Let {A,
B, C, D, E} represent the set of ice
cream flavors. 10 triple-scoop combi-
nations are available:
{ABC}{ABD}{ABE}{ACD}{ACE}{ADE}
{BCD}{BCE}{BDE}{CDE}
Each of these combinations is
available on either of the two cone
types. Thus, the total number of dis-
tinct triple-scoop cones having three
different ice cream flavors is 20.
25. The correct answer is (C). The

question asks you to select the choice
that does NOT describe sales
totaling at least 10,000. Choice (C)
describes 1.7K + 4.9K + 2.2K = 8.8K
sales, which is less than $10,000.
Choice (A) describes 8.5K + 1.9K =
10.4K sales. Choice (B) describes
7.5K + 1.0K + 2.0 + 0.8 = 11.3K sales.
Choice (D) describes 4.9K + 5.1K =
10.0K sales. Choice (E) describes
8.5K + 4.9K = 13.4K sales.
26. The correct answer is (A). The
number of basic models was 13,800
(the sum of all numbers in the
“Basic” column). The number of
standard models sold was 29,900
(the sum of all numbers in the
“Standard” column). The difference
is 16,100. To find the average
premium paid for a standard model,
divide $41,000,000 by $16,100.
Rounding these figures to $40
million and $16,000, the quotient is
$2,500.
27. The correct answer is (D).
Without the square hole, each of the
cube’s six outer surfaces contains 9
square inches, for a total of 54
square inches of outer surface area.
The square hole reduces that total

outer surface area by 2 square
inches, to 52. Each of the four inner
surfaces (inside the hole) accounts
for an additional 3 square inches, for
a total of 12 square inches of inner
surface areas. The solid’s total
surface area is 52 + 12 = 64 square
inches.
28. The correct answer is (B). Since x
is a negative number (less than 21),
x
3
is negative and x
2
is positive.
Hence, Quantity A is a negative
number less than x
3
. Quantity B, on
the other hand, is a positive number
greater than x
2
.
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Practice Test 2 435
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ANSWER SHEET PRACTICE TEST 3
Analytical Writing—Issue Task
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answer sheet
Practice Test 3
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