Answer:
a) 
b) 
Step-by-step explanation:
Number of balls in the urn = 12
Number of white balls in the urn = 4
So, number of balls which are not white = 12 - 4 = 8
We know that probability = No. of outcomes/Total number of outcomes
Let
denotes the event of getting white ball by A, B and C
a) each ball is replaced after being drawn.
Probability = Number of white balls/Total number of balls
Solution: 
b)the balls that are withdrawn are not replaced.
Solution:
If A wins: 
If A lost and B wins: 
If A and B lost and C wins: 
and so on....
Answer:
c
Step-by-step explanation:
Answer:
the one with 3/10 left has more
Step-by-step explanation:
because 1/5 is equal to 2/10 and 3/10>2/10