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The mean of five numbers is 8. when another number is added the mean is 7. find the number added

1 Answer

3 votes

Answer:


\large \boxed{\sf \ \ 2 \ \ }

Explanation:

Hello,

The mean of five numbers is 8 so we can write


(x_1+x_2+x_3+x_4+x_5)/(5)=8

When another number is added the mean is 7, let s note x the another number we can write


(x_1+x_2+x_3+x_4+x_5+x)/(6)=7

From the first equation we can say


x_1+x_2+x_3+x_4+x_5=8*5=40

So the second equation becomes


(x_1+x_2+x_3+x_4+x_5+x)/(6)=7\\\\<=> (40+x)/(6)=7\\\\<=>40 + x = 6*7=42\\\\<=> x = 42-40 = 2\\

The solution is then 2

Hope this helps

User Ankit HTech
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