GWD数学疑问汇总（所有问题可在此提问解答）

pig2009

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
为什么不选D选C呢？

if the average of the asseses values of x houses is $212,000 and the average of the assesed value of  y other houses is $194,000, what is the average of the assesed value of the x+y houses?

1)x+y=36

2)x=2y

为什么答案是C而不是B呢？

 At
        a
        fruit
        stand
        yesterday, the price of each apple was$0 .10 more than the price of each orange. What was the total revenue from the sale of oranges at the fruit
        stand
        yesterday.
(1)The number of oranges sold at the fruit stang yesterday was 5 more than the number of apples.
(2)The total revenue from the sale of appples at the fruit stangd yesterday was .$15.00

答案为什么是C而不是E？

If M is a positive integer, then M^3 has how many digits?

1) M has 3 digits

2) M^2 has 5 digits

答案是E，如何考虑此题?有NN能具体解释一下吗？

if x>1 and y>1,is x<y?

1)x^2/(xy+x)<1

2)xy/y^2-y<1

此题选E，trick在于2）中，y^2-y没有括号

last year in a group of 30 business,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 of the 30 businesses reported a net profit and had investments in foreign markets

2) last year 24 of the 30 businesses reported a ner profit or invested in forengn markets, or both

答案是B，为啥1）不行呢？

pig2009

the annual intrest rate earned by an investment increased by 10 percent from last year to this year. if the annual rate earned by the investment this year was 1 percent, what was the annual interest rate last year?

a)1% b)1.1% c)9.1% d)10% e)10.8%

pig2009

Does
                the
                decimal
                equivalent
                of
                p/q,
                where
                p
                and
                q are positive integers, contain only a finite number of nonzero digits?

(1) p > q

(2) q = 8
        

答案是E而不是B，为什么？

pig2009

2X+Y=12

|Y|=12

for how many ordered pairs (x,y) that 2 solutions of the system above are x and y both integers?

a)7 b)10 c)12 d)13 e)14

pig2009

the sum of positive integers a and y is 77,what is the value of xy?

1)x=y+1

2)x and y have the same tens digit

答案是D， 为什么不是A？

koncat

UP一下，1L的问题都是我要问的，再加一个

Q37.

AB

     +BA

AAC

In the correctly worked addition problem shown, where

the sum of the two-digit positive integers AB and BA is

the three-digit integer AAC, and A, B, and C are different digits, what is the units digit of the integer AAC?

A.      9

B.      6

C.      3

D.     2

E.      0

Answer E

我都凑出来AAC是110了AB是19 BA是11，答案怎么出来的