单选题If the average (arithmetic mean) of a, b, 4, and 10 is 8, what is the value of a + b?A 4B 6C 9D 15E 18
题目
单选题
If the average (arithmetic mean) of a, b, 4, and 10 is 8, what is the value of a + b?
A
4
B
6
C
9
D
15
E
18
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第1题：
The height of a light is measured from which reference plane?
A.Mean low water
B.Mean high water
C.Average water level
D.Geographical sea level
正确答案：B
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第2题：
计算连续区域B4到F8单元格的平均值的计算公式为（）
- A、SUM（B4，F8）
- B、AVERAGE（B4 F8）
- C、SUM（B4：F8）
- D、AVERAGE（B4：F8）
正确答案:D -
第3题：
问答题Kara attends a university where students study for an average (arithmetic mean) of 13.4 hours per week. How many hours per week does Kara study? (1) The standard deviation of study time at Kara’s school is 2.8. (2) Kara’s study time is one standard deviation away from the mean.正确答案： E解析：
（1）条件告诉了Kara学校学生学习时间的总标准差，无法计算Kara的学习时间数值；（2）条件指出Kara的学习时间距离平均数有两个标准差区间，不能确定其是高于还是低于平均值，故本题应选E项。 -
第4题：
单选题If the average of 8 and x is 10 and the average of 7 and y is 11, what is the average of x and y?A9.0
B10.5
C12.0
D13.5
E15.00
正确答案： C解析：
因为8和x的平均数为10，可得出(8+x)/2=10，x=12。又因为7和y的平均数为11，所以可得出7 + y = 22，y=15，所以x和y的平均值为(x+y)/2=(12+15)/2= 27/2=13.5。 -
第5题：
问答题If 10a + 10b =35, what is the average (arithmetic mean) of a and b?正确答案： 1.75解析：
由10a+10b=35可得10(a+b)=35→a+b=3.5，所以a和b的平均数是3.5÷2=1.75。 -
第6题：
单选题If the average (arithmetic mean) of 3, 7, 10, and x is 7, then what is the median of 3,7,10, and x?A5.5
B6
C6.5
D7
E7.5
正确答案： B解析：
因为3,7,10,和x 的平均数是7，可得出等式(3+7+10+x)/4=7，(20 + x)/4= 7，20+ x = 28，x = 8。所以3,7,10,和x四个数排序为3,7,8,10，它们的中位数为(7+8)/2=7.5。 -
第7题：
问答题What is the average (arithmetic mean) of x and y? (1) The average of x+3 and y+5 is 14. (2) The average of x,y and 16 is 12.正确答案： D解析：
将两条件分别代入计算可知，x和y的平均数均为10，故本题选D项。 -
第8题：
单选题The average (arithmetic mean) of a set of seven numbers is 81. If one of the numbers is discarded, the average of the remaining numbers is 78. What is the value of the number that was discarded?A98
B99
C100
D101
E102
正确答案： B解析：
If the average (arithmetic mean) of a set of seven numbers is 81, then the sum of these seven numbers is 7 x 81 or 567. Since, if one of the numbers is discarded, the average of the six remaining numbers is 78, the sum of these six numbers is 6×78 or 468. Since 567 - 468 = 99, the value of the number that was discarded is 99. -
第9题：
单选题Mean low water is the average height of（）.Athe surface of the sea
Bhigh waters and low waters
Call low waters
Dthe lower of the two daily low tides
正确答案： A解析： 暂无解析 -
第10题：
问答题If M is a set of five numbers p, q, r, s and t, is the range of numbers in M greater than 5? (1) The average (arithmetic mean) of p, q, r, S, and t is 5. (2) p-r>5.正确答案： B解析：
条件1不能判断M数集的极差；由p-r>5可知p、r间的距离大于5，故M的极差大于5，所以本题应选B项。 -
第11题：
单选题The average of the forward and after drafts is the（）.Amean draft
Btrue mean draft
Cmean of the calculated drafts
Ddraft at the center of flotation
正确答案： C解析： 暂无解析 -
第12题：
单选题The average (arithmetic mean) of five numbers is 10. The sum of three of the numbers is 30. What is the sum of the other two numbers?A5
B10
C20
D30
E40
正确答案： C解析：
The arithmetic mean of the five numbers is 10. That means the sum of the numbers is 50. The sum of three numbers is 30. so the sum of the remaining two numbers is 50-30 = 20. -
第13题：
The average height of the surface of the sea for all stages of the tide over a 19 year period is called ______.
A.mean high water
B.mean low water
C.half-tide level
D.mean sea level
正确答案：D
-
第14题：
在Excel2003中，C7单元格中有函数=AVERAGE（$C$3：$C$6），把它复制到C8单元格后，再双击C8，则该单元格中显示（）。
- A、=AVERAGE（C3：C6）
- B、=AVERAGE（$C$3：$C$6）
- C、=AVERAGE（$C$4：$C$7）
- D、=AVERAGE（C4：C7）
正确答案:B -
第15题：
单选题What is the average (arithmetic mean) of 8 consecutive odd integers if the smallest of those integers is n?An+5
Bn+6
Cn+7
Dn+8
En+9
正确答案： E解析：
最小的整数为n。它们是连续的奇数。这组整数为:n,n+ 2, n+4, n+6, n+8, n+10, n+12, n+14。计算这些整数的平均数即为将它们想加除于8。得出（8n+56）/8=n+7 -
第16题：
单选题The average (arithmetic mean) of c and d is 12, and the average of c, d, and e is 10. What is the value of e?A6
B10
C12
D18
E20
正确答案： A解析：
根据题目中已知的数量关系，可列等式如下：c+d= 12×2=24……①；c+d+e=10×3=30……②。把等式①代入等式②得，24+e=30，e=6。 -
第17题：
单选题If the set S is composed of the following numbers {99, 100, 100, 105, 106, 116, 123}, which of the following is largest?AThe average (arithmetic mean) of set S
BThe median of set S
CThe mode of set S
DThe range of set S
EThe standard deviation of set S
正确答案： A解析：
根据公式可知，A项S数集的平均数=107，B项S数集的中位数=105，C项S数集的众数=100，D项S数集的极差=24，E项S数集的标准差≈9，故本题选A项。 -
第18题：
单选题The average (arithmetic mean) of x and y is m, where m ≠ 0. What is the average (arithmetic mean) of x, y, and 2m?Am
B4/3m
C3/2m
D5/3m
E2m
正确答案： C解析：
因为x和y的算术平均数为m，所以x+y=2m，所以，所以x,y,2m的算术平均数为x+y+2m/3，因为x + y = 2m，所以x+y+2m/3=4m/3 -
第19题：
问答题If a is an integer, is b an integer? (1) The average (arithmetic mean) of a and b is an integer. (2) The average (arithmetic mean) of a, b, and b+4 is a.正确答案： D解析：
根据算数平均数的定义可知，本题应选D项。 -
第20题：
单选题If the average (arithmetic mean) of a, b, 4, and 10 is 8, what is the value of a + b?A4
B6
C9
D15
E18
正确答案： B解析：
根据题干可得出(a+ b + 10 + 4)/4=8，a + b=18。 -
第21题：
单选题If 70% of the bananas in a particular harvest had an average (arithmetic mean) length of 7 inches and 30% of the bananas in that harvest had an average (arithmetic mean) length of 5 inches, what was the average (arithmetic mean) length, in inches, of all of the bananas in the harvest?A6.0
B6.2
C6.4
D6.6
E6.8
正确答案： B解析：
假设共有100个香蕉，根据题干全部香蕉的长度为(100×70%×7)+(100×30%×5)=640英尺，共有100只香蕉，所以平均每只香蕉的长度为640/100=6.4。故选C。 -
第22题：
单选题在Excel2007中可以输入公式。下列公式写法正确的是（）。ASUM（A4：G10）
BH3*45+C9
C=AVERAGE（$B$8：B9，B$11，B$13）
D=MIN（AVERAGE（B8：B12）：AVERAGE（C8：C12）））
正确答案： C解析： 暂无解析 -
第23题：
单选题For integer values of the age from 10 months to 14 months, the average (arithmetic mean) weight falls approximately between ______ pounds.A750 and 850
B850 and 950
C950 and 1050
正确答案： A解析：
在10个月时，大象的体重大约为800磅，到了14个月大象的体重大约为1000磅，在这期间大象的体重变化比较平稳，因此体重平均数大约为900磅，故答案选B。 -
第24题：
问答题MegaTech and UltraCorp are considering a merger to form the MegaUltraTech Corporation. Does MegaTech have more employees than UltraCorp? (1) The average (arithmetic mean) age of UltraCorp employees is 32.8, while the average age of MegaTech employees is 27.2. (2) If the merger goes through and all employees from both companies remain employed, the average (arithmetic mean) age of the MegaUltraTech employees will be 31.4.正确答案： C解析：
条件1、2中均不涉及两个公司的员工数量，但是将两者综合可以推断出UltraCorp的员工数大于MegaTech，故本题选C项。