MathematicsIf the mean of the data is 8.1 and ∑fixi=132+5k,∑fi=20 , then k=

If the mean of the data is 8.1 and $\sum f_{i} x_{i} = 132 + 5 k, \sum f_{i} = 20$ , then $k =$

Mean

= 8.1

$\sum f i x i = 132 + 5 k$

$\sum f i = 20$

Mean $= \frac{\sum f i x i}{\sum f i}$

$\Rightarrow 8.1 = \frac{132 + 5 k}{20}$

$\Rightarrow 162 = 132 + 5 k$

$\Rightarrow 5 k = 162 - 132$

$\Rightarrow k = 6$

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