Question 823811
1/6+1/(c-2)-1/c=3/10
c=5
check
1/6+1/3-1/5=3/10
5/30+10/30-6/30=9/30
15-6/30=9/30
ok
or
10/3/6+10/3/(c-2)-10/3/c=1
-10/(3 c)+10/(3 (c-2))+5/9 = 1