[求助]GWD25 是答案有错吗？感谢！

COOKINGMAT

    

Q5

    

If x^3y^4=5,000, is y=5?

    

(1)y is a positive integer.

    

(2)x 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:C

个人认为是A， 高手帮忙！

    

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Q6

    

A string of 10 lightbulbs is wired in such
a way that if

    

any individual lightbulb fails, the entire string fails. If for

    

each individual lightbulb the probability of failing during

    

time period T id 0.06, what is the probability that the

    

string of lightbulbs will fail during time period T?

    

 

    

   A.0.06

    

   B.(0.06)^10

    

   C.1-(0.06)^10

    

   D.(0.94)^10

    

   E.1-(0.94)^10

    

Answer：E

这题是怎么个思路？

    

Q10

    

    
The sides of a square region, measured to the

    

         nearest centimeter, are 6 centimeters
long. The

    

         least possible value of the actual area of
the

    

         square region is

    

A.36.00 sq cm

    

B.35.00 sq cm

    

C.33.75 sq cm

    

D.30.25 sq cm

    

E.25.00 sq cm

    

Answer：C

个人认为是D，高手帮忙！

    

Q13

    

If the average (arithmetic mean) of the
assessed values

    

of x houses is $212,000 and the average of the assessed

    

values of y other houses is $194,000, what is the average

    

of the assessed values of the x+y houses?

    

 

    

(1)   
x+y=36

    

(2)   
x=2y

    

 

    

     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：C

个人认为是B，高手帮忙！

    

Q14

    

If a certain coin is flipped, the
probability that the coin will

    

land heads up is 1/2. If the coin is flipped 5 times, what is

    

the probability that it will land heads up on the first 3 flips

    

and not on the last 2 flips?

    

A.      3/5

    

B.      1/2

    

C.      1/5

    

D.     1/8

    

E.      1/32

    

answer：E

这题怎么个思路啊！

    

    

yinjihhh

1，x如果不是整数，可以任意数，可以是（1/2)x(2x5)^4

2,0.06 is the fail propability of one bulb, question is ask the fail rate of total 11 bulbs, it can be one fail,two fail, ...... or 11 fail. Therefore, the sucess rate of 11 bulbs at the same time should be calculated first. Then subtracted by 1.

3,I do not know, same answer with u.

4,0.5x0.5x0.5x0.5x0.5, each propability is same, is it right??

redhead

第三题的思路应该是:

因为只要一个灯泡坏了,整条都坏.所以考虑整条不坏的可能性, 一个灯泡不坏的可能性是1-0.06, 10个就是(1-0.06)^10.

1减去不坏的可能性就是整条线坏的可能性.

redhead

Q14

If a certain coin is flipped, the probability that the coin will

land heads up is 1/2. If the coin is flipped 5 times, what is

the probability that it will land heads up on the first 3 flips

and not on the last 2 flips?

A.      3/5

B.      1/2

C.      1/5

D.     1/8

E.      1/32

answer：E

这题怎么个思路啊！

这题的思路是:

前三次是headup的可能性为(1/2)^3.后两次不为headup的可能性为(1-1/2)^2, 所以全部的可能性是(1/2)^5=1/32.

yang_jing_8

Q10

    

    
The sides of a square region, measured to the

    

         nearest centimeter, are 6 centimeters
long. The

    

         least possible value of the actual area of
the

    

         square region is

    

A.36.00 sq cm

    

B.35.00 sq cm

    

C.33.75 sq cm

    

D.30.25 sq cm

    

E.25.00 sq cm

The side of the square should be greater than 5.5 centimeter, exclusive,  therefore  its  area  should be  more than  30.25 sq cm, exclusive. So the answer should be less than, and next to D . C is correct.

COOKINGMAT

感谢帮忙，明白了！


    

Q32.

    

Last year in a
group of 30 businesses, 21 reported a net profit and

    

15 had
investments in foreign markets. How many of the businesses

    

did not report a
net profit nor invest in foreign markets last year?

    

(1) last year 12
of the 30 businesses

    

   reported a net profit and had invest-

    

   ments in foreign markets.

    

(2) last year 24
of the 30 businesses

    

   reported a net profit or invested in

    

        

foreign
markets, or both.

    

    

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

    

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

    

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

    

l       
EACH
statement ALONE is sufficient

    

l       
Statements
(1) and (2) TOGETHER are NOT sufficient

                                                                                                                answer: B
                                                                                                            个人认为是D，高手再帮忙！