HSC 2013 Maths Marathon (archive) (8 Viewers)

[spanky125]

Re: HSC 2013 2U Marathon

A company that manufactures anal beads has a 2% chance of producing a defective anal bead. If it produces 8000 anal beads an hour for 12 hours a day. How many of defective anal beads will be produced in five working days?

 

[Drewk]

Re: HSC 2013 2U Marathon

a company that manufactures anal beads has a 2% chance of producing a defective anal bead. If it produces 8000 anal beads an hour for 12 hours a day. How many of defective anal beads will be produced in five working days?

9600? Hahaha

 

[Youi_]

Re: HSC 2013 2U Marathon

A company that manufactures anal beads has a 2% chance of producing a defective anal bead. If it produces 8000 anal beads an hour for 12 hours a day. How many of defective anal beads will be produced in five working days?

Total beads produced over 5 working days = 480,000

2% of 480,000 = 9,600 defective beads?

 

[spanky125]

Re: HSC 2013 2U Marathon

9600? Hahaha

Yes 9600

 

[Youi_]

Re: HSC 2013 2U Marathon

Parramatta Eels have a 0.1 chance of winning a game they play. How many games must be played so that they are 99% certain of winning.

 

[Triage]

Re: HSC 2013 2U Marathon

why do you use "7^x = e^(xln7)" ??

Because you can integrate and differentiate that. It's in the course somewhere

 

[spanky125]

Re: HSC 2013 2U Marathon

Parramatta Eels have a 0.1 chance of winning any game they play. How many games must be played so that they are 99% certain of winning.

99% certain? It doesn't matter how many games they play, if they have a 0.1 chance of winning any game they play then they will never get to 99%. From what you are saying previous results make no difference to the next games probability, therefore it will always be a 0.1 chance of winning.

 

[Youi_]

Re: HSC 2013 2U Marathon

99% certain? It doesn't matter how many games they play, if they have a 0.1 chance of winning any game they play then they will never get to 99%. From what you are saying previous results make no difference to the next games probability, therefore it will always be a 0.1 chance of winning.

edited

 

[Triage]

Re: HSC 2013 2U Marathon

99% certain? It doesn't matter how many games they play, if they have a 0.1 chance of winning any game they play then they will never get to 99%. From what you are saying previous results make no difference to the next games probability, therefore it will always be a 0.1 chance of winning.

I'm pretty sure he/she means how many games do they have to play for their to be 99% chance they have won one of them

 

[ocatal]

Re: HSC 2013 2U Marathon

 

[Youi_]

Re: HSC 2013 2U Marathon

I'm pretty sure he/she means how many games do they have to play for their to be 99% chance they have won one of them

He, and yes something along those lines. English HSC was last week I don't care much anymore about my grammatical skills until next year lol.

 

[Triage]

Re: HSC 2013 2U Marathon

I tried using the cosine rule for cos(90-alpha) in triangle apb but I'm getting (x^2 - 6)/4x

 

[ocatal]

Re: HSC 2013 2U Marathon

I tried using the cosine rule for cos(90-alpha) in triangle apb but I'm getting (x^2 - 6)/4x

That's correct. Are you sure you're applying the cosine rule correctly?

 

[Youi_]

Re: HSC 2013 2U Marathon

Let alpha=a for simplicity

 

[Triage]

Re: HSC 2013 2U Marathon

That's correct. Are you sure you're applying the cosine rule correctly?

Shit sorry. My calculator was giving me 2root5 squared as 10. My bad

 

[ocatal]

Re: HSC 2013 2U Marathon

Reasonably

Oh I realise what you've done. When squaring you must also square the 2 in the front. So you would get 4 x 5 = 20.

 

[Triage]

Re: HSC 2013 2U Marathon

Oh I realise what you've done. When squaring you must also square the 2 in the front. So you would get 4 x 5 = 20.

Yeah exactly.

 

[ocatal]

Re: HSC 2013 2U Marathon

Yeah exactly.

Not sure why you aren't getting x^2 -16 then.

 

[Triage]

Re: HSC 2013 2U Marathon

Not sure why you aren't getting x^2 -16 then.

Oh no I've got it now. My calculator was squaring it incorrectly

 

[Youi_]

Re: HSC 2013 2U Marathon

Oh no I've got it now. My calculator was squaring it incorrectly

Yes blame it on the infallible calculator <> hahaha my calculator sometimes loses its mind too.