GMAT数学(博智教材)第62页:If X is equal to the sum of the even integers from 40 to 60, inclusive, and y is the number of even integers from 40 to 60, inclusive, what is the value of x+y?
X=40+42+44......60=550
Y=(60-40)/2+1=11, 答案应该是561,为什么书后面的答案显示是560?
解答:
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解答:
sysadmin
提问:
有24个brand,对每个brand的四个方面进行评估,这四个方面是ABCD,评估结果有四种,excellent,good,not good,bad,至少有几个brand的两个方面either excellent or good?
(1)至少有10个brand的两个方面是excellent
(2)至少有12个brand的三个方面是good
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解答:
sysadmin老师
提问:
a/c是否小于1?
(1) a/(c-1)小于1
(2) (a-1)/c小于1
解答:
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解答:
sysadmin老师
提问:
切线与圆
解答:
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解答:
sysadmin老师
提问:
PS:总共66个学生,有18个是business major,24个是新生,还有36个什么也不是,我忘了最后是问,仅仅是新生不是business major 的还是仅仅是business major不是新生的?
构筑答案:好像答案不是12 就是16.。。
解析:
18和24代表的韦恩图圈圈有重合,36代表的是自己单独的圈圈。
Total =66; 36个学生不在Business和Fresh 范畴里面,所以F+B=30;
F 和B的共有学生=12,
是B不是F=6; 是F不是B=12。
If it took Carol 1/2 hour to cycle from his house to the library yesterday, was the distance that he cycled greater then 6 miles? ( 1mile=5,280feet)
(1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second.
(2) The average speed at which Carlos cycled from his house to the library yesterday was less than 18 feet per second
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解答:
sysadmin老师
提问:
Of the 12 temporary employees in a certain company, 4 will be hired as permanent employees. If 5 of the 12 temporary employees are women, how many of the possible groups of 4 employees consist of 3 women and one man?
A. 22
B. 35
C. 56
D. 70
E. 105
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解答:
sysadmin老师
提问:
if x is positive, is x >3
1. (x-1)^2 >4
2. (x-2)^2 >9
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解答:
sysadmin老师
提问:
if the average of the consecutive even integers a,b, and c is less than 13a, which of the following best describes the value of a?
答案: a is positive
为什么呢?