Probability question (1 Viewer)

[BlueGas]

I understand the answer to the first question, but the second and third question are weird. For the second question, I did (18/37)^6, but the answer says [(19/37)^5] x (18/37), why? Why is it even 19/37?

For the third question I done 1- (18/37)^6 but the answer says otherwise.

 

[rand_althor]

(ii): It is 19/37 as you can either get one of the 18 red slots or the green slot - 19 slots in total.
(iii): Is the answer 1 - (19/37)^5 ?

 

[BlueGas]

There's only 18 black slots, and the question is asking for black slots in part ii)

 

[rand_althor]

There's only 18 black slots, and the question is asking for black slots in part ii)

I meant for the first 5 games where the player does not get a black slot. The 6th game where the player does get a black slot is 18/37.

 

[BlueGas]

I meant for the first 5 games where the player does not get a black slot. The 6th game where the player does get a black slot is 18/37.

Oh so it's basically everything else other than back and then times by the probably you get black because it's the first time

 

[rand_althor]

Oh so it's basically everything else other than back and then times by the probably you get black because it's the first time

Yep. What was the answer to the third part?

 

[BlueGas]

Yep. What was the answer to the third part?

1 - (19/37)^5.

 

[psyc1011]

Why did you do 1 - (18/37)^6? Answer this before proceeding.

The question wants P(>= 1 black before 6th game) = 1 - P(0 blacks) = 1 - (P(red) + P(green)) = 1 - (18/37 + 1/37)^5

You probably missed the green ball OR you did (1 - P(all blacks)) - this is wrong, why?