Question

The mean of nine numbers is 77. If one more number is added to it then the mean increases by 5. Find the number added in the data.
Pls comment me the answer.

Answer 1

as according to me ur answer is
127

Answer 2

Answer:

The number added in the data = 127

Step-by-step explanation:

As per the question,

The mean of nine numbers = 77

Let the nine numbers be x₁, x₂, x₃, x₄, x₅, x₆, x₇, x₈ and x₉.

$Mean = 77 =\frac{x_{1}+x_{2}+x_{3}+x_{4}+x_{5}+x_{6}+x_{7}+x_{8}+x_{9}}{9}$

Let x₁ +x₂ + x₃ + x₄ + x₅ + x₆ + x₇ + x₈ + x₉ = X

$Mean = 77 =\frac{X}{9}$

X = 77 × 9 = 693

Now as per question, If one more number is added to it then the mean increases by 5, that is,

New mean = 77 + 5 = 82

Let the added number be = n

$82 =\frac{X + n}{10}$

or,

X + n = 82 × 10 = 820

693 + n = 820

n = 127

Hence, the number added in the data = 127