Question

Given a set `{3,6,2,-5,x,-12}`, for what x would the mean of the set be -10?

Answer 1

`x=-54`

Explanation:

The mean or average of a set `{X_i}` of data points is defined as

`barx=1/nsum_(i=1)^nx_i`

So in this particular case, if the mean is `-10`, then

`-10=1/6(3+6+2-5+x-12)`

`therefore -60=-6+x`

`therefore x=-54`