Question 250642
Currently let's assume there are N people.
The cost per person is 
{{{C1=200000/N}}}
Once 5 more people join then the cost per person is then
{{{C2=200000/(N+5)}}}
You know that 
{{{C2=C1-2000}}}
Substitute,
{{{C2=C1-2000}}}
{{{(200000/(N+5))=(200000/N)-2000}}}
{{{200000N=200000(N+5)-2000N(N+5)}}}
{{{200N=200(N+5)-2N(N+5)}}}
{{{200N=200N+1000-2N^2-10N}}}
{{{2N^2+10N-1000=0}}}
{{{N^2+5N-500=0}}}
{{{(N+25)(N-20)=0}}}
{{{N-20=0}}}
{{{N=20}}}
There are currently 20 people in the club.