Practice Exam 1 -Quantitative

Janny2018

When a certain tree was first planted, it was 4 feet tall, and the height of the tree increased by a constant amount each year for the next 6 years. At the end of the 6th year, the tree was taller than it was at the end of the 4th year. By how many feet did the height of the tree increase each year?

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• Is z equal to the median of the three positive integers x, y, and z ?
  
  (1) x < y + z
  (2) y = z
  
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    Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
    
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    Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
    
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    BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
    
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    EACH statement ALONE is sufficient.
    
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    Statements (1) and (2) TOGETHER are NOT sufficient.
    
  • If the terms of a sequence are t1, t2, t3, . . . , tn, what is the value of n ?
    
    (1) The sum of the n terms is 3,124.
    (2) The average (arithmetic mean) of the n terms is 4.
    
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      Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
      
    • 
      Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
      
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      BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
      
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      EACH statement ALONE is sufficient.
      
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      Statements (1) and (2) TOGETHER are NOT sufficient.
      
    • From a bag containing 12 identical blue balls, y identical yellow balls, and no other balls, one ball will be removed at random. If the probability is less than that the removed ball will be blue, what is the least number of yellow balls that must be in the bag?
      
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        17
        
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        18
        
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        19
        
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        20
        
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        21
        
        
      
      
      
    
    
    
  
  
  

痴人也有梦

1.2 * (4+4x )=4+6x
4.8+4.8x=4+6x
0.8=1.2x
x=2/3
         

痴人也有梦

Is z equal to the median of the three positive integers x, y, and z ?

(1) x < y + z
(2) y = z

首先Median是3个数中间的那个数字
条件1：   2 < 10-5  ; 2 < 5+3   Not suf
条件2： y=z  
三个数中有2个数是相等的，那中位数就是这两个相等的数...如果三个数都相等，同样的  所以suf

B

痴人也有梦

If the terms of a sequence are t1, t2, t3, . . . , tn, what is the value of n ?

(1) The sum of the n terms is 3,124.
(2) The average (arithmetic mean) of the n terms is 4.

条件1显然不行...无数可能  not suf
条件2 平均数为4...但其他啥都不知道...not suff

1+2:
总和为3124 , 平均值又为4...那么3124/4 = n  SUff

C

痴人也有梦

最后一题目：

蓝色球的可能性:   12 / (12+y) = 2/5
                                          y=18

所以一定要大于18 也就是最小为19

Janny2018

谢谢?