Probability. (1 Viewer)

[Paj20]

There is one seat at the back of the excursion bus that is very popular among the students.

Before the excursion, a draw is conducted to determine who will sit in the
popular seat. The names of the 12 students are placed in a hat and 3 names are drawn without replacement. The first name drawn determines who will sit in the seat on the first day. The second name drawn determines who will sit in the seat on the second day. The third name drawn determines who will sit in the seat on the third day.

(i) What is the probability that Jane’s name is the first drawn?

(ii) What is the probability that Jane’s name is the second drawn?

(iii) What is the probability that Jane’s name will NOT be one of the three
names drawn from the hat?


The book says the answer to the second one is 1/12. But how can it be when the first has already be drawn and they arnt replaced?

 

[o7nesss]

(i) 1/12

(ii) 1/11 (yea it should be 1/11 if the names are not being replaced...)


(iii) 9/12 = 3/4

im pretty sure those are right...
textbooks make mistakes...mine makes like 4 mistakes in spherical geometry...therefore...I SUCK A SPHERICAL GEOMETRY...and hate...i really hate spherical geometry!!!

...i said spherical geometry to many times...anyway...

HOPE THAT HELPS

 

[cxlxoxk]

There is one seat at the back of the excursion bus that is very popular among the students.

Before the excursion, a draw is conducted to determine who will sit in the
popular seat. The names of the 12 students are placed in a hat and 3 names are drawn without replacement. The first name drawn determines who will sit in the seat on the first day. The second name drawn determines who will sit in the seat on the second day. The third name drawn determines who will sit in the seat on the third day.

(i) What is the probability that Jane’s name is the first drawn?

(ii) What is the probability that Jane’s name is the second drawn?

(iii) What is the probability that Jane’s name will NOT be one of the three
names drawn from the hat?


The book says the answer to the second one is 1/12. But how can it be when the first has already be drawn and they arnt replaced?

i) 1/12
ii)1/11
iii)11/12 x 10/11 x 9/10 = 3/4
thanks savio

 

[savio23q]

(i)1/12

(ii)1/11

(iii) 11/12 x 10/11 x 9/10 = 3/4

 

[savio23q]

1/12
1/11
990/1728 for iii) is that right?

I don't think so. Use a tree diagram. Makes it so much easier.

Probability she wont get picked on the:

1st day - 11/12
2nd day - 10/11
3rd day - 9/10

multiple all 3 and you get 3/4

 

[cxlxoxk]

(i)1/12

(ii)1/11

(iii) 11/12 x 10/11 x 9/10 = 3/4

doh i did 11/12 x 10/12 x 9/12 lol i must be tired ur answers sound right.

 

[NEVAGIVEUP]

The answers are wrong, it should be
1/12
1/11; it is not being replaced
iii) 11/12 ?

 

[cxlxoxk]

probability is one of the areas i'm having trouble with. so my answers aren't accurate for this topic. is "zimmerman8k" right? cos i dunno.