求助几道不懂的GWD math

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Q12:

There are 11 women and 9 men in a certain club.  If the club is to select a committee of 2
women and 2 men, how many different such committees are possible?

A.     
120

B.     
720

C.     
1,060

D.    
1,520

E.     
1,980

Answer: E

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Q13:why
I got D?

Is the measure of one of the interior angles of
quadrilateral ABCD equal to 60 degrees?

(1)
          Two of the interior angles
of ABCD are right angles.

(2)
          The degree measure of angle
ABC is twice the degree measure of angle BCD.

A. Statement (1) ALONE is sufficient, but statement
(2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement
(1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient,
but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT
sufficient.

Answer: E

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Q14:
why I got B, the 1) is totally non sense

$10,000 is deposited in a certain account that pays r
percent annual interest compounded annually, the amount D(t), in dollars, that
the deposit will grow to in t years is given by D(t) = 10,000 {1+(r/100)}^t.  What amount will the deposit grow to in 3
years?

(1)
          D(t) = 11,000

(2)
          r =10

A. Statement (1) ALONE is sufficient, but statement
(2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement
(1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient,
but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT
sufficient.

Answer:

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Q23:

In the decimal representation of x, where 0 < x
< 1, is the tenths digit if x nonzero?

(1)
          16x is an integer.

(2)
          8x is an integer.

A. Statement (1) ALONE is sufficient, but statement
(2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement
(1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient,
but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT
sufficient.

Answer: B

Q32:
together xyz all > or=0? So for lx+yl=1x1+1y1 so x and y are all
bigger than 0?? How about x=y but all smaller than 0? X=-3 y=-3

If xyz
        ≠
0, is x (y + z) ≥ 0?

(1)   │y + z│ = │y│ + │z│

(2)
          │x + y│ = │x│
+ │y│

A. Statement (1) ALONE is sufficient, but statement
(2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement
(1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient,
but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT
sufficient.

Answer:

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Q33:

Each signal that a certain ship can make is comprised of 3
different flags hanging vertically in a particular order.  How many unique signals can be made by using
4 different flags?

A.          10

B.          12

C.          20

D.          24

E.          36

Answer: