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Please any one help me​

Please any one help me​-example-1

2 Answers

5 votes

Answer:

k=30

Explanation:

The formula for calculating the mean from a frequency table is:


\displaystyle \overline{x} = ( \sum \: fx)/( \sum f)

we have


  • \sum f = 30

  • \sum f x= 120 + 3k

  • \overline{x} = 7

So our equation is


\displaystyle 7= ( 120 + 3k)/(30) \\ \implies (120 + 3k)/(30) = 7

Solving the equation yields:


\implies 120 + 3k = 210 \\ \implies 3k = 90 \\ \implies \boxed{k = 30}

User Tom Cornebize
by
8.1k points
2 votes

Answer:

k = 30

Explanation:

The formula for the mean is:


\boxed{\displaystyle \text{Mean}=\overline{x}=(\sum fx)/(\sum f)}

where:

  • x = data value
  • f = frequency of each x

Given:


\displaystyle \sum f=30


\displaystyle \sum fx=120+3k


\overline{x}=7

Substitute the given values into the formula and solve for k:


\implies 7=(120+3k)/(30)

Multiply both sides by 30 to eliminate the denominator on the right side:


\implies 210=120+3k

Subtract 120 from both sides:


\implies 90=3k

Divide both sides by 3:


\implies k=30

Therefore, k = 30.

User Anders Waldenborg
by
7.5k points

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