Question

the mean of 10 numbers is 42 . if one number is included , the mean of the numbers becomes 45. find the number included in the list​

Answer 1

Given data : The mean of 10 numbers is 42 . If one number is included, the mean of the numbers becomes 45.

To find : Find the number included in the list ?

Solution : Now, according to given,

⟹ Mean of 10 numbers = 42

Here, we use formula of mean :

⟹ Mean = sum of the numbers/quantity of the number

⟹ 42 = sum of the number/10

⟹ sum of the number = 42 * 10

⟹ sum of the number = 420

Let, one number which included in 10 numbers be x,

Hence, here,

⟹ quantity of the numbers = 11

⟹ sum of the numbers = 420 + x and Mean = 45

Now, by formula of the mean

⟹ Mean = sum of the number/quantity of the number

⟹ 45 = (420 + x)/11

⟹ 45 * 11 = 420 + x

⟹ 495 = 420 + x i.e.

⟹ 420 + x = 495

⟹ x = 495 - 420

⟹ x = 75

Answer : The number included in the list is 75.

Answer 2

Answer:

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