Question 834477
p, how many in the pack.


Andy
{{{p-p/4}}} pieces remain

Alex
{{{p-p/4-(p-p/4)/4}}}  pieces remain

Lily
{{{p-p/4-(p-p/4)/4-(p-p/4-(p-p/4)/4)/3=36}}}  pieces remain


The rest of the solution is lengthy algebra steps.
You may want to simplify every iteration of paper sharing described before stepping through the "Lily" equation.  In fact, you may use the simplification upon each iteration to have a more manageable form of the "Lily" equation to solve.