ATAR Notes: Forum

Archived Discussion => Mathematics Exams => Math-Science-Tech Exams => VCE Exam Discussion 2016 => Exam Discussion => Victoria => Specialist Exam Discussion => Topic started by: asapwhat on November 07, 2016, 02:25:48 pm

Title: orange and lemon multiple choice q
Post by: asapwhat on November 07, 2016, 02:25:48 pm: Can someone throw me their solution to the orange and lemon mcq, for some reason I couldn't reach any of the given options.
Title: Re: orange and lemon multiple choice q
Post by: shortgame11 on November 07, 2016, 02:29:05 pm: think there wasnt an answer lol
Title: Re: orange and lemon multiple choice q
Post by: Matteus on November 07, 2016, 02:34:32 pm: Got 3root17 for the standard deviation??
Title: Re: orange and lemon multiple choice q
Post by: dave101 on November 07, 2016, 02:38:00 pm: Legitimately think I failed. Gussed about half of questions on multi choice, blanked out on so many questions. Rip me
Title: Re: orange and lemon multiple choice q
Post by: BNard on November 07, 2016, 02:41:57 pm: All this time I thought variance for combination of variables was a squared var(x) + bsquared var(y) but it wasn't an answer for mc:(
Title: Re: orange and lemon multiple choice q
Post by: chiiia on November 07, 2016, 02:44:59 pm: I got A (SD=3root29), only way it turned out as an answer.

Found sample SD of both oranges and lemons then squared it to get variance. Found 9*Var(oranges)+4*Var(lemons), then square rooted it.
Title: Re: orange and lemon multiple choice q
Post by: Callum@1373 on November 07, 2016, 02:47:43 pm: A for me, you got to the answer by not squaring the coefficient of the variance since it was repeat selection
Title: Re: orange and lemon multiple choice q
Post by: BNard on November 07, 2016, 02:54:20 pm: Temporarily using this as the exam discussion thread -

How did everyone go about finding the obtuse angle between the he paths of the vectors?
I had no idea, did some weird trig and got 90.4
Title: Re: orange and lemon multiple choice q
Post by: angrypotato1 on November 07, 2016, 02:57:19 pm: Quote from: Callum@1373 on November 07, 2016, 02:47:43 pm
A for me, you got to the answer by not squaring the coefficient of the variance since it was repeat selection

Yep can confirm

Quote from: BNard on November 07, 2016, 02:54:20 pm
Temporarily using this as the exam discussion thread -

How did everyone go about finding the obtuse angle between the he paths of the vectors?
I had no idea, did some weird trig and got 90.4

I got the gradients of the lines, then the tangent of each. Make a triangle, subtract from 180 to find the missing angle. Ended up with about 103?
Title: Re: orange and lemon multiple choice q
Post by: Eefy on November 07, 2016, 03:05:02 pm: Quote from: BNard on November 07, 2016, 02:54:20 pm
Temporarily using this as the exam discussion thread -

How did everyone go about finding the obtuse angle between the he paths of the vectors?
I had no idea, did some weird trig and got 90.4
I found the velocity vector of both ships and dot product. Ended up with around 97 degrees?
Title: Re: orange and lemon multiple choice q
Post by: tomp14 on November 07, 2016, 08:58:06 pm: I turned it into a triangle, found two angles and subtracted both from 180 to get around 97 degrees.