求助几道GWD数学题！呼唤好心人

苗苗心圃G · 发表于 2012-5-22 23:15:32

GWD4-Q1:这题我不明白题意。。。。
Of the fruit that arrives at a cannery, 20 percent by weight is rejected before processing.Of the fruit that is processed, 15 percent by weight is rejected before canning.Of the fruit that arrives at the cannery, what percent by weight is canned?

A.32%
B.35%
C.65%
D.68%

E.70%

GWD4-Q4:这题我一开始选的A
For a nonnegative integer n, if the remainder is 1 when 2ⁿ is divided by 3, then which of the following must be true?

I.n is greater than zero.
II.3ⁿ = (-3)ⁿ
III.√2ⁿis an integer.

A.I only
B.II only
C.I and II
D.I and III
E.II and III

Q13:这题我没领会啥意思呢。。。答案是C，我选的B
Lists S and T consist of the same number of positive integers.Is the median of the integers in S greater than the average (arithmetic mean) of the integers in T?
(1)The integers in S are consecutive even integers, and the integers in T are consecutive odd integers.
(2)The sum of the integers in S is greater than the sum of the integers in T.

求好心人赐教啊！

GWD4-Q4:这题我一开始选的A
For a nonnegative integer n, if the remainder is 1 when 2ⁿ is divided by 3, then which of the following must be true?

I.n is greater than zero.
II.3ⁿ = (-3)ⁿ
III.√2ⁿis an integer.

A.I only
B.II only
C.I and II
D.I and III
E.II and III

Q13:这题我没领会啥意思呢。。。答案是C，我选的B
Lists S and T consist of the same number of positive integers.Is the median of the integers in S greater than the average (arithmetic mean) of the integers in T?
(1)The integers in S are consecutive even integers, and the integers in T are consecutive odd integers.
(2)The sum of the integers in S is greater than the sum of the integers in T.

求好心人赐教啊！

苗苗心圃G · 发表于 2012-5-22 23:16:11

呃。。。一不小心把二三题发了两遍。。。。

gina2012 · 发表于 2012-5-22 23:28:19

the first one is straightforward,

ask you from the original fruit coming in to what has been made in cans, what is the percentage of those in can divided by the original

(1-20%) times (1-15%) = 68%

gina2012 · 发表于 2012-5-22 23:30:17

the first one is straightforward,

ask you from the original fruit coming in to what has been made in cans, what is the percentage of those in can divided by the original

(1-20%) times (1-15%) = 68%

gina2012 · 发表于 2012-5-22 23:35:01

the second one

if the remainder is 1 when 2n is divided by 3,

this sentence means that n is either 0 or even times multiple of 2

so I and II

苗苗心圃G · 发表于 2012-5-23 23:53:12

谢谢！
请问第三题咋解呢？

gina2012 · 发表于 2012-5-24 00:01:22

From 1,
S={2,4,6} and T={1,3,5}
or
S={2,4,6} and T={3,5,7}
Insufficient

From 2
S={1,2,10} and T={1,2,3}
or
S={1,5,6} and T={1,2,3}
Insufficient

Combining both:
Same number of positive integers.
S consecutive even integers
T consecutive odd integers
Sum(s)>Sum(t)
For this, t's starting point needs to be smaller than s's starting point
So, AM of T < Median of S
Sufficient.

Note: I am assuming here that "S and T consist of the same number of positive integers" means "S and T contain only positive integers and total number of integers is same". If we dont assume this, total number of integers (that includes negative numbers) in S and T becomes unknown, leading to E.

this one, I too view the question wrong, so I did a little search. It is simple.

I think GMAt is tricky because they delibrately put the quesion to confuse you.

求助几道GWD数学题！呼唤好心人

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