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2 years ago

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

Mathematics

1 answer:

sasho [114]2 years ago

4 0

Answer:

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

Step-by-step explanation:

Hello,

The mean of five numbers is 8 so we can write

$\dfrac{x_1+x_2+x_3+x_4+x_5}{5}=8$

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

$\dfrac{x_1+x_2+x_3+x_4+x_5+x}{6}=7$

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

$\dfrac{x_1+x_2+x_3+x_4+x_5+x}{6}=7\\\\ \dfrac{40+x}{6}=7\\\\40 + x = 6*7=42\\\\ x = 42-40 = 2\\$

The solution is then 2

Hope this helps

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