Question 953904
Since the terms are in arithmetic sequence,the middle term is equal to average of first and the last term. 

so, for {{{32}}},{{{k}}},{{{3}}}the middle term {{{k=(32+3)/2=35/2}}} or as decimal {{{k=17.5}}}

or this way:

It's an arithmetic sequence so the difference between consecutive terms is constant.
the first difference is {{{32-k}}} and the second difference is {{{k-3}}}, so we have
{{{32-k =k -3}}}

{{{32+3 =2k }}}

{{{35/2=k}}}