Answer:
let the number of yellow balls be x
then probability of picking yellow ball is x/12
without replacement , probability of picking another yellow ball would be (x-1)/11
probability of picking two yellow balls would be x/12(x-1)/11 =5/33
x2-x=5x132/33=660/33=20
x2-x= 20
x2-x-20=0
(x-5)(x+4)=0
x=5 or x=-4
we disregard x= -4 hence x=5
Step-by-step explanation:
