求解数学题2道.........新补充一题,谢谢高手赐教!

junqiaopeng · 发表于 2011-3-1 10:22:59

[attachimg=221,210]85166[/attachimg]
Q3: The figure shows a square patio surrounded by a walkway of width x meters.If the area of the walkway is 132 square meters and the width of the patio is 5 meters greater than the width of the walkway, what is the area of the patio, in square meters?
A.56
B.64
C.68
D.81
E.100

Q1, If w and c are integers, is w > 0?
(1) w + c > 50
(2) c > 48
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.

Q2,For a convention, a hotel charges a daily room rate of $120 for 1 person and x dollars for each additional person. What is the charge for each additional person?
(1) The daily cost per person for 4 people sharing the cost of a room equally is $45.
(2) The daily cost per person for 2 people sharing the cost of a room equally is $25 more than the corresponding cost for 4 people.
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.

sdcar2010 · 发表于 2011-3-1 11:51:19

1 E. C could be 49 or 4900.

2 D. 120 + 3 x = 180; x = 20. (120 + x)/2 = 25 + (120 + 3x)/4; x =20

junqiaopeng · 发表于 2011-3-1 15:50:58

感谢楼上,此处藏龙卧虎啊~~~~

第一题,我选C,正疑惑不解呢. 谢谢!

xbx_lee · 发表于 2011-3-1 16:31:53

感谢楼上,此处藏龙卧虎啊~~~~

第一题,我选C,正疑惑不解呢. 谢谢!

-- by 会员 junqiaopeng (2011/3/1 15:50:58)

这位早就不是“藏”龙了，是显龙。

junqiaopeng · 发表于 2011-3-1 17:22:49

额....小弟初来乍到,不好意思.

再请教一道,谢谢前辈们赐教 :
The figure shows a square patio surrounded by a walkway of width x meters. If the area of the walkway is 132 square meters and the width of the patio is 5 meters greater than the width of the walkway, what is the area of the patio, in square meters?
A. 56
B. 64
C. 68
D. 81
E. 100
[attachimg=221,210]85165[/attachimg]
谢谢.

sdcar2010 · 发表于 2011-3-1 20:47:45

Let the width of the square = x. Then the width of the walkway = x-5. Then the width of the bigger square defined by the the outer sides of the walkway is (x+2*(x-5)). Then the area of the walkway is simply the difference between the areas of the two squares:
132 = (3x-10)^2 - x^2
132 = 8x^2 -60x +100

x = 0.5 or 8

So x = 8 since it has to be bigger than 5.

junqiaopeng · 发表于 2011-3-1 21:06:01

Thanks,I got it,but i find that the question is wrong:the right side of the graph should be "x", not "2 in".I calculated by "2 in" for calculation.

Thank you very much.

求解数学题2道.........新补充一题,谢谢高手赐教!

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