Question

. If the mean of frequency distribution is 7.5 and ∑fi xi = 120 + 3k, ∑fi = 30, then k is equal to:​

Answer 1

Given:

Mean of the distribution=7.5

∑fi xi = 120 + 3k

∑fi = 30

To find:

The value of k

Solution:

The value of k is 35.

We can find the value by following the steps given below-

We know that the mean of a distribution can be obtained by dividing the sum of elements of the distribution by the total number of elements in the distribution.

∑fi xi denotes the sum of the entire distribution and ∑fi denotes the number of elements in the distribution.

The mean of the distribution=7.5

So, the mean=∑fi xi/ ∑fi

On putting the values, we get

7.5= (120+3k)/ 30

7.5×30= 120+3k

75×3=120+3k

225=120+3k

225-120=3k

105=3k

k=105/3

k=35

Therefore, the value of k is 35.

Answer 2

Answer:

K is equal to 35

Step-by-step explanation:

Granted:

Distribution mean = 7.5

Fi xi = 120 + 3k

Fi = 30

Search:

The value of k

Solution:

The value of k is 35.

We can see the value by following these steps -

We know that the meaning of a distribution can be obtained by dividing the sum of the distribution elements by the total number of distribution elements.

∑fi xi means the sum of the whole distribution and ∑fi means the number of elements in the distribution.

Distribution average = 7.5

Therefore, the mean = ∑fi xi / ∑fi

When setting the values ​​we get

7.5 = (120 + 3k) / 30

7.5 × 30 = 120 + 3K

75 × 3 = 120 + 3K

225 = 120 + 3K

225-120 =3K

105 = 3K

k = 105/3

k = 35

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