- #1
Dell
- 590
- 0
4 balls are placed randomly into 10 bins,
what is the probability that exactly 8 of the bins will be empty??
first i need to find out how many ways i can place the balls into the bins --> 10*10*10*10=10000
now i need to find how many ways the balls can be placed so that there are 8 empty bins- or in other words that there are 2 not empty bins
so i choose 2 random bins out of the 10
10C2 = 45
now i need to place the 4 balls
1, 3
2, 2
3, 1
all in all 3 ways
45*3/10000=0.0135,,
the correct answer is 0.63
what is the probability that exactly 8 of the bins will be empty??
first i need to find out how many ways i can place the balls into the bins --> 10*10*10*10=10000
now i need to find how many ways the balls can be placed so that there are 8 empty bins- or in other words that there are 2 not empty bins
so i choose 2 random bins out of the 10
10C2 = 45
now i need to place the 4 balls
1, 3
2, 2
3, 1
all in all 3 ways
45*3/10000=0.0135,,
the correct answer is 0.63