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Zorluk: OrtaMean, Median, and Mode

A data set consists of five positive integers a,b,c,d,a, b, c, d, and ee, written in non-decreasing order (abcdea \le b \le c \le d \le e). The set has a unique mode of 88, a median of 1010, and an arithmetic mean of 1212. If the range of the set is 1414, what is the value of the largest integer ee?

  1. A
    17
  2. B
    20
  3. 22Cevap
  4. D
    24
  5. E
    26

Cevap

22
The median of a 5-element ordered set is the middle element, so c=10c = 10. Because 8 is the unique mode and is strictly less than 10, the first two numbers must both be 8 (a=8,b=8a = 8, b = 8). The range is 14, meaning the difference between the maximum element ee and the minimum element aa is 14. Therefore, e=8+14=22e = 8 + 14 = 22.

Adım Adım Çözüm

1
Determine the median value cc
c=10c = 10
In an ordered 5-element set, the median is the 3rd element.
2
Determine the values of aa and bb using the unique mode
a=8a = 8 and b=8b = 8
Since 8 is the unique mode and 8<108 < 10, 8 must appear at least twice in the first two positions.
3
Calculate the largest integer ee using the given range
e=a+14=8+14=22e = a + 14 = 8 + 14 = 22
The range of a set is the difference between the maximum (ee) and minimum (aa) values.
4
Verify consistency with the mean
Sum =5×12=60= 5 \times 12 = 60; d=60(8+8+10+22)=12d = 60 - (8 + 8 + 10 + 22) = 12, which satisfies 10122210 \le 12 \le 22.
Ensures all set conditions (mean of 12, non-decreasing order, unique mode) are satisfied.

Anahtar Kavram

Relating Mean, Median, Mode, and Range in Ordered Data Sets
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