Hi

I should be very grateful if someone a lot cleverer than me could kindly look at this and give me an answer.

bag with one white, red, black ball. random picks.

how often black ball chosen 4; 5; 6 times in a row.

Many thanks in anticipation of your help with this.

Dave

The odds of choosing any particular ball are 1/3 on a single pick. So the odds of choosing the black ball n times in a row in n picks are just (1/3)^n.

Unless, the chosen ball is not returned to the bag. In such a case, the odds are approximately 0.000000000000.

The title of your post made me click for an entirely different reason than you intended (prolly).

I was hoping for an epic images thread

Are there cases of people having three testicles?

Edit: I see polyorchidism is very rare but is a known congenital disorder.

Epic 1st post. I guess it shows that I have maturity issues when I can't resist clicking on a "3 balls" thread thinking I'm going to get something other than a question about calculating probability.

i think the lead singer of crash test dummies has this

thanks Bohr 8346

I don't know what that means?

Dave

This only applies if the ball is put back in ( duh! ) and you only want the chance of getting a black ball in straight picks ( i.e. not 3 blacks in 5 picks etc, but only black black black in 3 picks ).

The chance of getting a black ball ( like any other ball ) is 1/3. To get the final chance you multiply that chance per itself as many times as you want black balls in a row.

Example: 4 black balls in a row -> 1/3 x 1/3 x 1/3 x 1/3
Example: 6 black balls in a row -> 1/3 x 1/3 x 1/3 x 1/3 x 1/3 x 1/3

If you want to get the chance of 4 black balls in 6 tries, including the various combinations, the equation get's more complicated.

If you still don't understand how it works, you might want to try in your native language somewhere.

Step 1: Figure out your chances that you pick it one time if there are three balls. It's one in three, 1/3, or 33%. (If you had 4 balls it would be 1/4, 5 balls 1/5, and so on.)

Step 2: To figure the odds of picking that ball a certain number of times in a row you just multiply the number of picking it once by itself. (So for twice its 1/3 x 1/3, for 10 times you do 1/3 x 1/3 x 1/3.... 10 times.

Challenge Question

If you have 4 balls and non of them are alike, what are the odds you pick the same ball 100 times in a row? Use only a basic calculator without the ^ that you didn't understand. Show all your work and give your answer in your next post and show all your work. If you do that I bet you end up deciding that there MUST be an easier way and it will lead you to figure out what the ^ is for by the end of it all :-)