Further Math Exam 1: Answers + Discussion!

[chickadee]

Can someone please explain Question 8 in Number patterns is B and not A?

[RipeBanana]

can anyone explain Q 7 on Networks.
Why is it E? isn't the one on the very left the only graph that is planar?

[soysauce]

Can someone please explain Question 8 in Number patterns is B and not A?

Can't be A because straight line = arithmetic

[aejays]

Hey sorry to ask again, but what did everyone get for Graphs & Relations question 5?

When I checked with a friend, he got all the same as me except question 5 in graphs about the average speed of the train.
What he did was find the average of the two periods of time the train was actually moving, and excluded the time it stopped, so he got D (65) as the answer.
I took "the average speed of the train...for the journey" to mean for the whole journey and ended up with A (45).

[Lucho23]

Hey sorry to ask again, but what did everyone get for Graphs & Relations question 5?

When I checked with a friend, he got all the same as me except question 5 in graphs about the average speed of the train.
What he did was find the average of the two periods of time the train was actually moving, and excluded the time it stopped, so he got D (65) as the answer.
I took "the average speed of the train...for the journey" to mean for the whole journey and ended up with A (45).

You're correct Unfortunately, your friend didn't get it correct because the average time includes the stationary time.

[LiquidPaperz]

how many stupid mistakes did people make?

[soysauce]

how many stupid mistakes did people make?

too many..............

[vididid]

how many stupid mistakes did people make?

so many, I had 4 questions where i had the right answer and having finished 10 minutes early felt the need to over think like a retard and changed them ugh... but the other 4 were actual errors

[doomdestroyer]

how many stupid mistakes did people make?

Too many, i always do that for Maths, not one of my strongest subjects.

[_mariiam]

Hey everyone

My friend got a B on further today but shes rank one
Will she still get a 40 or above??!!!??
(she's not on Facebook so she asked me to ask for her)

[AngelWings]

Can someone please explain Question 8 in Number patterns is B and not A?

Note that it uses AC and that you already have a pair of similar sides: 40.4m from BC and 10m from BD.
After that, use the SF concept: SF= BC/BD=AC/DE
Where did we get DE, you ask?

Spoiler

You use Pythagoras' theorem! So...
DE² = 12²- 10²
DE=square root of 44

After finding DE, you know want to find the distance AC.
Use the SF concept

Spoiler

So...
BC/BD=AC/DE
where BC=40.4m , BD=10m, DE= square root of 44 (also metres) ~ we worked this out before.
therefore: 40.4/10=x/sqrt (44)
x=sqrt of 44 x 4.04 = 26.7983 (4dp.) = 26.8
This gives B.

[clidedescope]

Hey everyone

My friend got a B on further today but shes rank one
Will she still get a 40 or above??!!!??
(she's not on Facebook so she asked me to ask for her)

If she got a B on the second exam, I don't think she would. SAC marks are only 33% of your score, so it makes your exam performance crucial to get a good mark, even though she is ranked first.
I can't say for sure, but I think she'd need an A+ in exam 2 to get in the 40s.

[Stew_822]

I'm not sure about question 4 in Geometry and Trig. How did you guys get C? I can't even replicate it.

I got A by doing tan (23) = opposite over 150, because there was 150m difference between the heights of the two points and we are looking for the horizontal (not straight-line) distance. You draw the triangle and work it out.... right.... c'mon guys please.. don't let me lose another mark here :/

[Dan1995]

I'm not sure about question 4 in Geometry and Trig. How did you guys get C? I can't even replicate it.

I got A by doing tan (23) = opposite over 150, because there was 150m difference between the heights of the two points and we are looking for the horizontal (not straight-line) distance. You draw the triangle and work it out.... right.... c'mon guys please.. don't let me lose another mark here :/

You needed to do tan (67) as the angle inside the triangle is 90-23

[soysauce]

I'm not sure about question 4 in Geometry and Trig. How did you guys get C?

Angle of depression = 23
90 - 23 = 67

Now make a right angle triangle, height = 150, length = ?, angle between height and hypotenuse = 67
tan(67) = x/150
x = 150 * tan(67)