Question

The mean of five numbers 3,7,9,12, and x is 8. Find the value of x

Answer 1

Answer: " x = 9 " .
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Step-by-step explanation:
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To calculate the mean:
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The mean =

{the sum of all the values in the number set} ÷

{the number of values in the data set} ;
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To solve for "x" ;
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Given that the "mean" is: "8" ;
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8 = { 3 + 7 + 9 + 12 + x } / 5 ;
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↔ { 3 + 7 + 9 + 12 + x } / 5 = 8 ;
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→ { 3 + 7 + 9 + 12 + x } = 8 * 5 ;
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→ { 31 + x } = 40 ;
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↔ x + 31 = 40 ;
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Subtract "31" from EACH SIDE of the equation; to isolate "x" on one side of the equation; and to solve for "x" ;
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→ x + 31 − 31 = 40 − 31 ;

→ x = 9 .
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