Question

Bag a contains 6 white balls and 4 black balls and bag b contains 3 white balls and 2 black balls. A white ball is picked from bag a and put into bag
b. Then, three balls are picked from bag b and put into bag
a. Find the probability that a ball picked now from bag a is black.

Answer 1

Answer:

2/5

Step-by-step explanation

the person is putting it inside again so the Total no. of balls after taking balls are same .

so THEREFORE 4/10 =2/5

Answer 2

Bag A = 6 white and 4 black = 10 total

Bag B = 3 white and 2 black = 5 total

now

Bag A = 5 white and 4 black = 9 total

Bag B = 4 white and 2 black = 6 total

three balls are picked from bag B and put into bag A Find the probability that a ball picked now from bag A is black.

case 1 ; all three white = Bag A ; 8 white + 4 black ; 4/12 * 4c3/6c3 = 1/15

case 2 ; 2 white and 1 black ; Bag A ; 7 white + 5 black ; 5/12* 4c2*2c1/6c3= 1/4

case 3 ; 1 white and 2 black ; Bag A; 6 white + 6 black ; 6/12 *4c1*2c2/6c3= 1/10

total probability that a ball picked now from bag A is black = 1/15+1/4+1/10= 5/12