Quick Probability Question

jaws104 · 13 Jan 2016 at 14:39

Feeling bit sorry for myself here after an exam, will spare the details but simply put;

5 possible topics
3 questions
2 topics studied

* only need to answer 1 of the three questions!

So chance neither two studied topics turning up ? I'm fairly rubbish at probability but looks like

(3/5)*(2/4)*(1/3) = 9%

Any maths head care to confirm before i go get the vodka out of the fridge? :mad:

cheesyboy · 13 Jan 2016 at 14:43

Correct

Was this a question in the exam, or is it a real life conundrum where you only studied two topics and ended up drawing dead in the exam

jaws104 · 13 Jan 2016 at 14:44

This is real life dude

Zogger · 13 Jan 2016 at 14:54

clearly 100%. It's a law of the universe that whatever you didn't study comes up.
If you had studied 4 topics you would have had 2 questions about the 5th one.
If you had studied 5 topics you would have found out you'd been studying the wrong topics.

It's quantum physics

dl8860 · 13 Jan 2016 at 15:04

^ I'll have what he's smoking

doofer · 13 Jan 2016 at 15:06

Zogger said:
clearly 100%. It's a law of the universe that whatever you didn't study comes up.
If you had studied 4 topics you would have had 2 questions about the 5th one.
If you had studied 5 topics you would have found out you'd been studying the wrong topics.

It's quantum physics

Sod's Law.

R.C.Anderson · 13 Jan 2016 at 17:21

I had a similar exam like that in my first year at uni, but I think it was 5 topics, 3 questions, and had to answer 2.

Can't remember the maths I did for it now, but pretty sure I revised enough that there was a 100% chance I could answer at least 1 question, and ~90% chance I could answer 2, so I stopped revising