mathematics 2007 shcool certificate...help (1 Viewer)

[Riot09]

pretty much i'm going through past papers and there heaps that i don't know how to do...so these questions are the one im not sure how to do..and theres some iv done but im not sure if its right.
so working out please and a explanation please.

All answers will be appreciated and im very aware that its the holidays so thank you for taking youre time to read and/ or answer these.

http://www.boardofstudies.nsw.edu.au/schoolcertificate/2007/mathematics-sc-test-07.pdf

non-calculator section

q.8 (is there a way to do this question)

q.9(i worked it out to be -6,if it is or not can you tell me why)

q.11 its a diagram question

q.13 a fishing boat drops a crab pot every 10 minutes

how many hours does it take to drop 96 crab pots?i got 160 hours)

q.14 is another diagram question

q.16 sam multiplies 2 whole numbers together,and gets an answer of 231

neither of the 2 numbers is 1

what could the 2 numbers be? (is there another procedure other than trial and error)

q.17 another diagram question that blows uo my head

q.18 calculate(3x10^4)x(2x10^-6),expressing your'e answer in scientific notation

q.22 complete 2p(......)=6p^2-2p

q.24

q.25 (diagram question) and can you tell me the steps to the working out also

section 2

q.29 the plateosaurus was a dinosaur that lived about 220million years ago.

what is this number in scientific notation?

q.31 multiple choice (explain please)

q.39 and 40statistics questions

q.43

6x^0+7=13 (but how)

q.it is estimated that a person ingests 4.5 litresof pesticides and hebicides per year.

how many mm per day does this represent?

q.48.diagram question

51.the area of a circle is 100pi square metres.

what is the diameter of this circle?

52.diagram statistic question the answer is b but how?

54.find the solution of the equation 5x-4/2=10

55.what is the reciprocal of 4^-2

56.gemma stacks 4 block,each a different colour,on top of one another to create a "tower"

how many different 'towers' can she make if she puts all 4 blocks in a different order each time?(is there a short way to do this question)

59.colin sold a dvd player for $180.this was $60 less than colin originally paid for it.

what was colin's loss as a percentage of his cost price?

60.diagram question

61.statistics diagram question

65,66,67,6973,74,75 diagram question(i really suck at those)

q.68 erica earns $6 per hour.robert earns $8 per hour.last week they both earned the same amount of money,which was more than $100.

what is the least number of hours that erica could have worked last week?

q.70,71,72,79,81 and 82 b and d,

and questions 83 and 84 would be a life saver also

its not that i dont do my homework its just that this is year 7,8,9 stuff that iv forgotten thats all.proberly because i was playing too much halo 3 and graw 1 online alot during those 3 years.

 

[FTW]

thats practically the whole paper.....
I'll answer some later, I'm not in the mood right now...

 

[Riot09]

yeagh i know,alright

 

[supre]

9. n=<-6
(u cross multiply)
11. angleDEF= angleABC because it has been scaled up by two.
16. 7 and 33
22. 2p(3p-p)
section 2
29. (C)
31. (B) 13/200(its in %)
43. (C)

i m bored now i will do the rest in a while.

 

[Riot09]

alright thanx,and is ur tag named after the actual store supre? or the car supra?.

 

[supre]

alright thanx,and is ur tag named after the actual store supre? or the car supra?.

LOL. None actually i just like the name in itself.

 

[supre]

q.43

6x^0+7=13 (but how)

anything with the power of 0 to something is the number by itself. so 6x^0 is just 6 and 6+7=13

 

[supre]

51. area of circle is always (pie R^2)
100 pie=10^2 therefore radius=10 and diametre is double the radius so the answer is 20 (C)
52. u take the median of the age and times it by the frequency/ total frequency
54. u cross multiply so would be 5x-4=20
5x=20+4/ 5x=24/x=24/5 simplified version is 4 and 4/5 so its (C).
55. reciprocal means rotating a fraction or something so reciprocal of 2 would be half (1/2)
for this one 16 (D)
59. collin paid $180+60=$240/ loss%=60/240*100=25% (A)
60. thats an isoscles triangle therefore its 180/3= 60 (angle sum of triangle) (C)
66. (B)
68. it says more than $100 therefore 100/6= 16.666666...
so the nearest one is $18 so its (B)
70. maggie=y
lisa=y+3
bart=2(y+3)
adding them together is 4y+9 (D)
72. 2:5 that has been simplified and they are asking the value of a to c so it is 8:15 (D)

 

[Amogh]

q.it is estimated that a person ingests 4.5 litresof pesticides and hebicides per year.

how many mm per day does this represent?
1litre = 1000 ml
so 4.5 litre = 4500 ml per year
there are 365 days in an year
So answer is 4500/365 = ...

q.48.diagram question
Use Pythagoras Theorem to find the diaganol. (Hyp. of the triangle)
its just root (2*8^2) = root 128
then add the three sides

51.the area of a circle is 100pi square metres.

what is the diameter of this circle?
Area of circle = pi*r^2
so d = 2r = 2*root 100 = 20m


52.diagram statistic question the answer is b but how?
you find the average of the class interval.
For example, for the first one: you add 15+29 and then divide by 2. You then take this and multiply with the corresponding frequency, then divide by the total number of frequencies.

54.find the solution of the equation 5x-4/2=10
You shold have written this as (5x-4)/2 = 10..else its misleading
awrites so that is 5x -4 = 20
x= 24/5

55.what is the reciprocal of 4^-2
4^-2 = 1/16. The reciprocal of that is 16.

56.gemma stacks 4 block,each a different colour,on top of one another to create a "tower"

how many different 'towers' can she make if she puts all 4 blocks in a different order each time?(is there a short way to do this question)
At first you have 4 options, then 3 options, then 2, and then just one.
so its 4*3*2*1 = 24

59.colin sold a dvd player for $180.this was $60 less than colin originally paid for it.

what was colin's loss as a percentage of his cost price?
so colin bought it for = 180+60 =240
Loss percentage = (loss/cost price) * 100
that is, (60/240) * 100 = 25%

60.diagram question
Not sure but i think its 90 degrees as the diagonal of a square bisects the angles.

61.statistics diagram question

65,66,67,6973,74,75 diagram question(i really suck at those)
1369*6


q.68 erica earns $6 per hour.robert earns $8 per hour.last week they both earned the same amount of money,which was more than $100.

what is the least number of hours that erica could have worked last week?
100/6 = around 17 atleast.

q.70
Lisa = 3 +y
Bart = 2(3+y)
Maggie= y (given)
so maggie + lisa + bart = 9+4y

71
Let normal rate be xSo last week, 38x + 1.5*6*x = 2219.34
solve for x.

72,79,81 and 82 b and d,

and questions 83 and 84 would be a life saver also

will do later if i get time

proberly because i was playing too much halo 3 and graw 1 online alot during those years.
lol i'll play you

 

[supre]

83. (a) 0.12*$20 000=$2400
(b) simple interest= P*R*T
SI=20 000*7%*4= $5600
(c) $5600+20 000=$25600
(d) balance+interest=$25600 over 4 years, every month so there are 48 months in 4 years so 25600/48=$533.333...

 

[supre]

i have solved question 84 on my notebook and attached it with this post.
hope i have helped.
:apig::apig:

 

[Omnipotence]

anything with the power of 0 to something is the number by itself. so 6x^0 is just 6 and 6+7=13

No, anything by the power of 0, will equate to 1.

1. x^0 = 1 (Since no brackets)
2. 6 x 1 = 6
3. 6 + 7 = 13

 

[Omnipotence]

i have solved question 84 on my notebook and attached it with this post.
hope i have helped.
:apig::apig:

You did a slight mistake.
84A is correct.
However the other three were wrong.
84B. Asks for length, not area. Its actually 3.4+3.4+6.2+1.4+1.7+1.7= 17.8m
84C. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds. However it needs to be to the nearest degress and thus the answer = 24 degrees.

Supre, you did the correct working out but you got the wrong answer. Careless mistake, lol.

84D. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds, as you can see the triangle happens to be isosceles since it has two equal sides and hence it will have two angles equal.

Multiply angle BAX by 2 = 48 degrees, 36 minutes and 32.76 seconds.

Angle sum of a triangle is 180 degrees, using this theorem we subtract 48 degrees, 36 minutes and 32.76 seconds (This is the answer, a shortcut method using rational thinking. However the conventional way, is as follows) from 180 degrees which will = 131 degrees, 23 minutes and 27.24 seconds.

Notice that line BA is bisected by YX and the by using the angles of a straight line which equals to 180 degrees. Subtract 131 degrees, 23 minutes and 27.24 seconds from 180 degrees and you'll end up with the same answer from above which is 48 degrees, 36 minutes and 32.76 seconds. The question asks for the number to be placed to the nearest degree in which the answer would be 49 degrees.

 

[supre]

You did a slight mistake.
84A is correct.
However the other three were wrong.
84B. Asks for length, not area. Its actually 3.4+3.4+6.2+1.4+1.7+1.7= 17.8m
84C. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds. However it needs to be to the nearest degress and thus the answer = 24 degrees.

Supre, you did the correct working out but you got the wrong answer. Careless mistake, lol.

84D. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds, as you can see the triangle happens to be isosceles since it has two equal sides and hence it will have two angles equal.

Multiply angle BAX by 2 = 48 degrees, 36 minutes and 32.76 seconds.

Angle sum of a triangle is 180 degrees, using this theorem we subtract 48 degrees, 36 minutes and 32.76 seconds (This is the answer, a shortcut method using rational thinking. However the conventional way, is as follows) from 180 degrees which will = 131 degrees, 23 minutes and 27.24 seconds.

Notice that line BA is bisected by YX and the by using the angles of a straight line which equals to 180 degrees. Subtract 131 degrees, 23 minutes and 27.24 seconds from 180 degrees and you'll end up with the same answer from above which is 48 degrees, 36 minutes and 32.76 seconds. The question asks for the number to be placed to the nearest degree in which the answer would be 49 degrees.

OOps, thanks for the correction though...

 

[ninetypercent]

you guys are champions

 

[Amogh]

You did a slight mistake.
84A is correct.
However the other three were wrong.
84B. Asks for length, not area. Its actually 3.4+3.4+6.2+1.4+1.7+1.7= 17.8m
84C. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds. However it needs to be to the nearest degress and thus the answer = 24 degrees.

Supre, you did the correct working out but you got the wrong answer. Careless mistake, lol.

84D. Angle BAX = 24 degrees, 18 minutes and 16.38 seconds, as you can see the triangle happens to be isosceles since it has two equal sides and hence it will have two angles equal.

Multiply angle BAX by 2 = 48 degrees, 36 minutes and 32.76 seconds.

Angle sum of a triangle is 180 degrees, using this theorem we subtract 48 degrees, 36 minutes and 32.76 seconds (This is the answer, a shortcut method using rational thinking. However the conventional way, is as follows) from 180 degrees which will = 131 degrees, 23 minutes and 27.24 seconds.

Notice that line BA is bisected by YX and the by using the angles of a straight line which equals to 180 degrees. Subtract 131 degrees, 23 minutes and 27.24 seconds from 180 degrees and you'll end up with the same answer from above which is 48 degrees, 36 minutes and 32.76 seconds. The question asks for the number to be placed to the nearest degree in which the answer would be 49 degrees.

Exterior angle theorem
Exterior angle of a triangle = Sum of interior opposite angles
Hence <BYX = 2 * <BAX
You applied the "Sum of angles in a triangle" and the "Linear pair" theorems, albeit this would have been the quickest way of solving this.