Cam has a collection of ceramic chickens. 10% of the chickens were given to him as gifts, and he bought the rest himself. If 11 chickens were given to him as gifts, how many chickens does he have in total?
Let C be the total number of chickens.
He bought C-11 chickens because 100-10=<<100-10=90>>90% were bought
This means 90% of the chickens equaled C-11, and each percent is C-11/90
The total amount of chickens is C=C-11/90 * 100
100=C/90(C-11)
9000=C(C-11)
9000=C^2-11C
C^2-11C-9000=0
The numbers that multiply to -9000 and add to -11 are -100 and 90
(C-100)(C+90)=0
C=100 or -90
Chickens can't be negative so he has 100 chickens. Answer: \boxed{100}.