Mean of 10 observations (numbers) is 20. If one number is included, the mean becomes 21, the included number is : 1. 431 2. 31 3. 231 4. 131

Given: Number of observations = 10 Mean = 20 Let `a` be the sum of all observations. Mean = ⇒ 20 = ⇒ 20 x 10 = a ⇒ 200 = a Let `b` be the number added to the observation. New mean = 21 New mean = ⇒ 21 = ⇒ 21 x 11 = 200 + b ⇒ 231 = 200 + b ⇒ b = 231 - 200 ⇒ b = 31 Hence, option 2 is the correct option.

The mean of x - 2, x, x + 2, x + 4 is :
x + 1
x
4x + 4
x + 2

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Mean of 20 observations (numbers) is 30. If one number is excluded, the mean of remaining numbers becomes 28. The excluded number is :
532
1132
68
572

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If each observation of the data is decreased by 15; then the mean :
remains same
is increased by 15
is decreased by 15
is multiplied by 15

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If the mean of x₁ and x₂ is 12.5 and mean of x₁, x₂ and x₃ is 16. The value of x₃ is :
32
3.5
285
23

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Mathematics

Mean of 10 observations (numbers) is 20. If one number is included, the mean becomes 21, the included number is :
431
31
231
131

Statistics

Related Questions

The mean of x - 2, x, x + 2, x + 4 is :
x + 1
x
4x + 4
x + 2

Mean of 20 observations (numbers) is 30. If one number is excluded, the mean of remaining numbers becomes 28. The excluded number is :
532
1132
68
572

If each observation of the data is decreased by 15; then the mean :
remains same
is increased by 15
is decreased by 15
is multiplied by 15

If the mean of x₁ and x₂ is 12.5 and mean of x₁, x₂ and x₃ is 16. The value of x₃ is :
32
3.5
285
23

Mathematics

Mean of 10 observations (numbers) is 20. If one number is included, the mean becomes 21, the included number is :43131231131

Statistics

Related Questions

The mean of x - 2, x, x + 2, x + 4 is :x + 1x4x + 4x + 2

Mean of 20 observations (numbers) is 30. If one number is excluded, the mean of remaining numbers becomes 28. The excluded number is :532113268572

If each observation of the data is decreased by 15; then the mean :remains sameis increased by 15is decreased by 15is multiplied by 15

If the mean of x1 and x2 is 12.5 and mean of x1, x2 and x3 is 16. The value of x3 is :323.528523

Mean of 10 observations (numbers) is 20. If one number is included, the mean becomes 21, the included number is :
431
31
231
131

The mean of x - 2, x, x + 2, x + 4 is :
x + 1
x
4x + 4
x + 2

Mean of 20 observations (numbers) is 30. If one number is excluded, the mean of remaining numbers becomes 28. The excluded number is :
532
1132
68
572

If each observation of the data is decreased by 15; then the mean :
remains same
is increased by 15
is decreased by 15
is multiplied by 15

If the mean of x₁ and x₂ is 12.5 and mean of x₁, x₂ and x₃ is 16. The value of x₃ is :
32
3.5
285
23