Question

Question #894c8

Answer 1

`20`

Explanation:

`(75 + 83 +84+84 +74 + x) / 6 = 70`

`(75 + 83 +84+84 +74 + x) = 70 xx 6`

`(75 +83 +84 +84 +74 +x ) = 420`

`(400 +x ) = 420`

`x = 20`

Answer 2

20

Explanation:

`color(blue)("What the mean value actually is")`

The mean is that single value which if you multiply it by the count of all the contributing values you have the sum (addition) of all those numbers.

Example: `2 + 5+3+10 = 20`

The mean is `("the sum")/("the count")->(2+5+3+10)/4 =20/4=5`

`"Mean value "xx" count" -> 5xx4=20`
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`color(blue)("Answering the question")`

All buts the last score are 75, 83, 84, 84, and 74

Let the last score be represented by `x`
The total count of values is 6 if you include `x`

So the addition of all the separate values should give us
`6xx" mean value" ->6xx70=420`

So what we should have is:

`75+ 83+ 84+ 84+ 74+x = 420`

So

`x=420-(75+ 83+ 84+ 84+ 74)`

`x=420-400`

`x=20`
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`color(blue)("Check")`

`(75+ 83+ 84+ 84+ 74+20)/6=70 color(red)(larr" As required")`