Question 1029724
p, the number of students expected;  p-20, the actual number of students who paid.  The purchase cost is the same either way.


Original group member price,  {{{120/p}}}.


Smaller group member price, {{{120/p+25}}}.
This smaller group was {{{p-20}}} members.


{{{highlight((120/p+25)(p-20)=120)}}}