Probability Question

[Norman Bates]

A student is taking part in a course that consists of 8 different lessons. For the final test , 3 of the 8 are chosen of which the student has to answer 1.
A student prepares only 2 of the eight lessons in order to minimize his work.

1. What is the number of the possible cases?

2.What is the number of the cases in which one or two lessons he prepared are asked?

3. What is the probability of his plan succeeding?


I think number 1. is 8! / 3! 5! but i´m not sure what the answer for number 2. and 3. is.
Can someone solve this problem?

 

[DcupSheepNipples]

Probability Question

Pick up Ice Pick!
Place at base of skull!
Insert in head!
Problem Solved!

 

[Norman Bates]

bump

 

[bwood]

the answer is w...

 

[Norman Bates]

the answer is w...

I´ll keep that as backup answer if Dcup´s plan does not work

 

[DigitalKyle]

there are 56 possible combinations of three-section-sets to be tested over.

 

[Norman Bates]

good, than i have that first part correct. You know how to continue with part 2 and 3?

 

[biteme]

#3. He can be tested on 8 different lessons. He has an equal chance of being tested on any one question. He studied for 2. The probability that his plan will succeed is 25%. It's been a long time since I had statistics, but I think that's correct. I don't think it matters that 3 of 8 lessons will be picked to choose from. The likelihood is that any 1 of the 8 could be in the final 3. On # 2 I'm not sure, the way you worded the question, I think there is 2 possible answers, I'll have to go back and look. Don't take this answer as gold, I'm not sure.

 

[Norman Bates]

Thx biteme.

let me translate the questions once more:

1. the number of possible cases

2. the number of favourable cases ( that´s the word to word translation)

one more thing: there are 3 credits on number 1, 8 on number 2 and 2 on number 3