Question

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

Answer 1

`\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