Question

From a bag containing 8 green and 5 red balls, there are drawn one after the other. The probability of all three balls being green if the balls drawn are replaced before the next ball is picked and the balls drawn are not replaced are respectively? *

Answer 1

Answer: 512/2197 and 336/1716

Step-by-step explanation:

green balls = 8

red balls =5

total balls = 13

now 3 balls are drawn with replacement

probability of drawing first green ball = 8/13

now it is replaced and total balls in the bag remains same

hence probability of drawing second green ball = 8/13

similarly probability of drawing third green ball= 8/13

now the probability that all 3 balls are green = (8/13).(8/13).(8/13) = 512/2197  Ans.

now ball are not replaced then

probability of first green ball = 8/13

probability of second green ball = 7/12

probability of third green call = 6/11

now the overall probability of all 3 ball are green  = (8/13).(7/12).(6/11) = 336/1716  Ans.