Question 940801
Difference between successive terms is a constant.

{{{4p-60=2p-6-4p}}}
{{{6p-60=-6}}}
{{{p-10=-1}}}
{{{highlight(p=9)}}}


The three terms are:  60, 36, 12
Common difference is {{{-24}}}.


General term,  {{{highlight(60-(n-1)24)}}}.
n is the index for the term.



The general term is usually stated as {{{A[1]+(n-1)d}}}, but you know from your specific example that d=-24, so subtraction is shown for the general term of your example.  You would evaluate {{{60-(19)(24)}}}.