further questions

[vce08]

Pythagoras.
Length = ((65+240)^2 + 50^2)^1/2

(i don't know how to use latex)

[clinton_09]

48 repayments of 480 over 4 years = 48 * 480 = 23040

loan is $18000 so interest = 23040 - 18000 = 5040

annual r% = (100 * Interest) / (Principal * Time)

so, (100 * 5040) / (18000 * 4) = 7%

effective interest rate = annual interest rate * [2 (number of repayments) / (# of repayments + 1)]

so, 7 * 96/49 = 13.7%

yes! i get that now, thanks!!!

[jsimmo]

Pythagoras.
Length = ((65+240)^2 + 50^2)^1/2

(i don't know how to use latex)

EDIT: Don't worry. I understand it now!!! lol thanks  these are so simple yet I can never know where to draw the triangle! lol

[SP3CIALIS7]

EDIT: nevermind realized there was in fact no decimal between 18 and 5, it was just a small dot of ink from my printer *facepalm*

Anyone looked at NEAP 2007 Q 13 of core
I got an answer that was not an option, and I have idea what I did wrong.

I correctly identified Spring 2007 as quarter 8 and subbed into the equation [Sales= 18.5 + 38.9 x quarter number] then multiplied that answer by springs seasonal index of 1.02.
They used the same technique in the answers but somehow got that 18.5 + 38.9 x 8 = 492.6 ? Is this an error

[ReVeL]

Heres a question that is a little confusing.

A statistically minded athlete has evaluated her 400m efforts. She has noticed that the date shows a bell shaped distribution with a mean of 65.2 seconds and a standard deviation of 1.3

If she runs a time of 66.8 seconds, which of the following statements is closest to summarising her effort?
A. This time is in the top 16% of her efforts.
B. This time is in the bottom 16% of her efforts.
C. This time is close to the average of her efforts.
D. This time is in the top 2% of her efforts.
E. This time is in the bottom 2% of her efforts.

Now, at first glance it doesn't appear to difficult.

Her z score can be calculated to be

Now this would place her result in the highest 16%, so we can eliminate C,D,E.

BUT, my question is, because it is a race, wouldn't this be in her WORST 16% of efforts considering the aim of a race is to run as quickly(lowest time) as possible, as opposed to most questions(eg. lengths of a nail)? She ran ABOVE the mean, hence would make sense for this to be a 'bad' run and be in the worst 16%.

I eventually put A which was given as the correct answer in the solutions but I'm sort of uncertain.

What do other people think?

[Noblesse]

Heres a question that is a little confusing.

A statistically minded athlete has evaluated her 400m efforts. She has noticed that the date shows a bell shaped distribution with a mean of 65.2 seconds and a standard deviation of 1.3

If she runs a time of 66.8 seconds, which of the following statements is closest to summarising her effort?
A. This time is in the top 16% of her efforts.
B. This time is in the bottom 16% of her efforts.
C. This time is close to the average of her efforts.
D. This time is in the top 2% of her efforts.
E. This time is in the bottom 2% of her efforts.

Now, at first glance it doesn't appear to difficult.

Her z score can be calculated to be

Now this would place her result in the highest 16%, so we can eliminate C,D,E.

BUT, my question is, because it is a race, wouldn't this be in her WORST 16% of efforts considering the aim of a race is to run as quickly(lowest time) as possible, as opposed to most questions(eg. lengths of a nail)? She ran ABOVE the mean, hence would make sense for this to be a 'bad' run and be in the worst 16%.

I eventually put A which was given as the correct answer in the solutions but I'm sort of uncertain.

What do other people think?

Did this question yesterday, I also choose A, but yeah IMO it should be B

[vce01]

yeah i would've thought it was B too,  :/ given that the time she took was just outside one S.D that would've meant she was either top 1but i had a different way of working it out6% or bottom 16%. since she took longer that means it was in the bottom 16%. that was my way..probably not perfect tho. whats the z score got to do with it, can somebody explain?

[ReVeL]

yeah i would've thought it was B too,  :/ given that the time she took was just outside one S.D that would've meant she was either top 1but i had a different way of working it out6% or bottom 16%. since she took longer that means it was in the bottom 16%. that was my way..probably not perfect tho. whats the z score got to do with it, can somebody explain?

It's not essential. I only used it to show that her run was greater than 1 standard deviation from the mean(because her z score was 1.23), hence would be in the highest 16%.

You don't have to use this method though.

[vce01]

ohhh yeah, i forgot about how that worked. thanks probably would be a better method to use

lol i just realised my earlier post was fucked up, i meant to edit something but i forgot. 

[SP3CIALIS7]

Yeah that question confused me, I put B in practical application I have always been taught to watch out for the context i.e. if its a game of golf lower score=higher. This seemed to be completely disregarded here, but I doubt there'd be anything that ambiguous on the exam.

[clinton_09]

http://www.vcaa.vic.edu.au/vce/studies/mathematics/further/pastexams/2005/2005furmath1.pdf

Could someone help me with question 5 and 8 in Geo and Trig

Thanks guys

[plato]

Q5 - Draw a diagram and label TX&Y
At each of these three ponts, draw a vertical line to represent North at each point
At Y, the line YX is at a bearing of 302 degrees and so the angle between the North line and the line YX is 58 degrees.
At point X, this is the same as the angle between XY and the North line there.
At pont T, the angle between the North line and the line TX is 55 degrees.
This is the same as the angle bewteen TX and the North line at X
Therefore, the angle TXY = 55+58=113 degrees which is answer E


Q8

The area has been increased by a factor of 2250/1440 = 1.5625
If you were to increase the lengths of a shape in two dimensions by a factor of 1.25, then the area would increase by the square of 1.25 which gives 1.5625.
In this question then, you need to find the sqaure root of the area enlargement factor to find the length enlargement factor.

Therefore, the length of 36 is multiplied by 1.25 to give 45 metres as the answer B

[Noblesse]

Ok, the answer is E
Here is an awesome image to help