2008 practice math school certificate emergency........help (1 Viewer)

[Riot09]

can you please help me with these 2008 school certificate questions because i have no idea how to solve them,please include working out and a explanation with the answer.Thank you:

Q.55 what is the area of the largest circle that can fit inside a square of side lenght 6cm?

a.36cm^2 b.6pie cm^2 c.9pie cm^2 d.36cm^2

Q.57 (2d over e)^3

Q.60 what is the equation of the line through(4,5)parallel to the y-axis

Q.61 which set of measurements cannot be the side lenghts of a triangle

a. 3cm,4cm,5cm b.3cm,5cm,7cm c.3cm,6cm,8cm, b.3cm,7cm,11cm

Q.69 a large corporation donated money to community groups.local schools received $255 000.this represented 17% of the total money donated.the surf life association received $135 000

what percentage of the total money donated was given to the surf life saving association

Q.74 one year from now,naomi will be one-third of her mothers age.her mother is now 38 years old.

in how many years from now will naomu be half her mothers age?

Q.79 this is a set of scores 18,20,25,38

a whole number score between 18 and 38 is added to the set of scores

for the new set of scores,indicate whether each of the following is correct or incorrect.

a.the mean of the scores could stay the same.

b.the mean of the scores could decrease.

c.the median of the scores could stay the same

d.the median of the scores could decrease

Q.80 during an election between 2 candidates,the count of the votes was

isaac 5000 votes
sam 4700 votes

there were 1000 postal votes still to be counted,it is known that more than half the postal votes will go to sam and isaac will get at least 20% of the postal votes.

indicate whether each of the following is correct or incorrect

a.isaac could win by 250 votes
b.sam could win ny250 votes
c.isaac could win by 300 votes
d.sam could win by 300 votes

Q.82 in a pre-olympic tournament,archers fire at the target shown below.Naren fires 20 arrows at the target and his results are recorded in the table below.

target score frequency

1 2
2 6
3 7
4 2
5 3

(b) .what is the relative frequency of target score 4?

(c).show that the mean of his scores is 2.9

(d).naren fires 20arrows.to qualify for the next round of the tournament he must score an overall mean greater than 4 from the 40 arrows.

explain,with calculations,why naren cannot progress to the next round.


thanks for the answers.

 

[ninetypercent]

Q.55 what is the area of the largest circle that can fit inside a square of side lenght 6cm?

a.36cm^2 b.6pie cm^2 c.9pie cm^2 d.36cm^2

area of circle = pi x r^2
radius = 3 cm
area of largest circle = 3^2 x pi = 9pi

(C)

Q.57 (2d over e)^3

(2d)^3/e^3 = 8d^3/e^3

Q.60 what is the equation of the line through(4,5)parallel to the y-axis

Think about it. The line goes through (4,5). It is parallel to y axis, so therefore it is a vertical line. the line must be y = 5.

Q.69 a large corporation donated money to community groups.local schools received $255 000.this represented 17% of the total money donated.the surf life association received $135 000

what percentage of the total money donated was given to the surf life saving association

255 000 = 0.17a
a = 1 500 000
percentage for surf life saving = 135000/1500000 = 9%

Q.74 one year from now,naomi will be one-third of her mothers age.her mother is now 38 years old.

in how many years from now will naomu be half her mothers age?

let naomi's age be n and her mother's age be m

n + 1 = 1/3(m+1)
m = 38
n + 1 = 1/3(39)
n + 1 = 13
n = 12
naomi is 12 years old

let x by the years from the present

12 + x = 1/2(38 + x)
12 + x = 19 + 1/2x
1/2x = 7
x = 14 years

Q.79 this is a set of scores 18,20,25,38

a whole number score between 18 and 38 is added to the set of scores

for the new set of scores,indicate whether each of the following is correct or incorrect.

a.the mean of the scores could stay the same.

b.the mean of the scores could decrease.

c.the median of the scores could stay the same

d.the median of the scores could decrease

a) current mean = 25.25. for it to stay the same = 25.25 x 5 = 126.25. The total of the five scores must be 126.25. This is not possible, since a WHOLE NUMBER is being added to the scores. Hence the statement is FALSE
b) TRUE. If 19 is added, the mean would be 24.
c) FALSE. the current median is 22.5. It will only stay the same if 22.5 were added, but this is not a whole number
d) TRUE. If 21 were added, this would be the new median => which is less than 22.5

 

[scardizzle]

area of circle = pi x r^2
radius = 3 cm
area of largest circle = 3^2 x pi = 9pi

(C)



(2d)^3/e^3 = 8d^3/e^3



Think about it. The line goes through (4,5). It is parallel to y axis, so therefore it is a vertical line. the line must be y = 5.



255 000 = 0.17a
a = 1 500 000
percentage for surf life saving = 135000/1500000 = 9%



let naomi's age be n and her mother's age be m

n + 1 = 1/3(m+1)
m = 38
n + 1 = 1/3(39)
n + 1 = 13
n = 12
naomi is 12 years old

let x by the years from the present

12 + x = 1/2(38 + x)
12 + x = 19 + 1/2x
1/2x = 7
x = 14 years



a) current mean = 25.25. for it to stay the same = 25.25 x 5 = 126.25. The total of the five scores must be 126.25. This is not possible, since a WHOLE NUMBER is being added to the scores. Hence the statement is FALSE
b) TRUE. If 19 is added, the mean would be 24.
c) FALSE. the current median is 22.5. It will only stay the same if 22.5 were added, but this is not a whole number
d) TRUE. If 21 were added, this would be the new median => which is less than 22.5

+1 for being bothered to answer so many q' s

 

[Schoey93]

Salve scardizzle! Come stai oggi? Mi chiamo James e studio italiano. E tu studi italiano anche? Mi dispiace se tu non capisci il mio messaggio! Ciao ciao!

 

[ninetypercent]

+1 for being bothered to answer so many q' s

I didn't answer all of them.. Someone else can do the rest

 

[FTW]

Q.61 which set of measurements cannot be the side lenghts of a triangle

a. 3cm,4cm,5cm b.3cm,5cm,7cm c.3cm,6cm,8cm, d.3cm,7cm,11cm

I noticed you hadn't answered this one so I'll do it ninety

Answer: is D 3,7,11

11 is the longest side so it must be the hypotenuse and 3+7 is not greater than 11 :. lines of length 3cm,7cm and 11cm cannot be a triangle (if it helps you to understand get a ruler and try to draw it, its not possible.)

 

[scardizzle]

Salve scardizzle! Come stai oggi? Mi chiamo James e studio italiano. E tu studi italiano anche? Mi dispiace se tu non capisci il mio messaggio! Ciao ciao!

just to clarify im not actually italian so I have no idea what you just said. I take latin at school and salve is the latin for hello obviously this has remained so in the italian langauge anyway... Latin FTW

 

[Amogh]

I think these questions havent been answered yet...and so,

Q.61 which set of measurements cannot be the side lenghts of a triangle
a. 3cm,4cm,5cm b.3cm,5cm,7cm c.3cm,6cm,8cm, b.3cm,7cm,11cm
The sum of two sides of a triangle HAS to be more than the third side. so only D does fails to meet this criteria. (3+7 =10, which is <11)

Q.82 in a pre-olympic tournament,archers fire at the target shown below.Naren fires 20 arrows at the target and his results are recorded in the table below.
target score frequency
1 2
2 6
3 7
4 2
5 3
(b) .what is the relative frequency of target score 4?
R.F is just the probability (The ratio of the number of observations to the total number of observations)
2/20 = 1/10

(c).show that the mean of his scores is 2.9.
Multiply the 'target score' with the frequency. (We basically want to add all the data, then divided it with the number of outcomes).
So, its (2+12+21+8+15)/20 = 2.9


(d).naren fires 20arrows.to qualify for the next round of the tournament he must score an overall mean greater than 4 from the 40 arrows.
explain,with calculations,why naren cannot progress to the next round.
Naren has fired 20 arrows and has 20 left to attain a mean of 4.
A mean greater than 4 means a total of atleast 160 (4X40).
His current total score is 58.(2+12+21+8+15)
So, he needs 102 (160-58) more points.
Even with the highest points for all the remaining 20 arrows, naren can only add 100 more points. (5*20)
Hence he can at most achieve a final score of 158, which falls 2 short of qualifying.

I don't think i've missed out any unanswered questions.
Tell me if I have.

 

[Amogh]

I noticed you hadn't answered this one so I'll do it ninety

Answer: is D 3,7,11

11 is the longest side so it must be the hypotenuse and 3+7 is not greater than 11 :. lines of length 3cm,7cm and 11cm cannot be a triangle (if it helps you to understand get a ruler and try to draw it, its not possible.)

Nowhere is it said that the triangle is right angled.

 

[ninetypercent]

I think I recall using the cosine rule for that triangle question before. I basically used it to determine which triangles were impossible based on the fact that cos theta must be between -1 and 1.
WHY THE HELL IS MY COMPUTER SO SLOW!!!!!!!!!!

 

[mastistar]

let naomi's age be n and her mother's age be m

n + 1 = 1/3(m+1)
m = 38
n + 1 = 1/3(39)
n + 1 = 13
n = 12
naomi is 12 years old

let x by the years from the present

12 + x = 1/2(38 + x)
12 + x = 19 + 1/2x
1/2x = 7
x = 14 years

I bow down to you man...thx for this..i always wondered how to do this..thx for your efforts! +1 rep

Salve scardizzle! Come stai oggi? Mi chiamo James e studio italiano. E tu studi italiano anche? Mi dispiace se tu non capisci il mio messaggio! Ciao ciao!

Translation:

Hello scardizzle! How are you today? My name is James and study Italian. And you study Italian as well? I'm sorry if you do not understand my message! Hello hello!

 

[Riot09]

+1 for scardizzle and 90%

 

[Riot09]

Q.57 (2d over e)^3 can someone please explain this question to me

 

[Riot09]

q.80 would be appreciated
Q.80 during an election between 2 candidates,the count of the votes was

isaac 5000 votes
sam 4700 votes

there were 1000 postal votes still to be counted,it is known that more than half the postal votes will go to sam and isaac will get at least 20% of the postal votes.

indicate whether each of the following is correct or incorrect

a.isaac could win by 250 votes
b.sam could win ny250 votes
c.isaac could win by 300 votes
d.sam could win by 300 votes

 

[scardizzle]

Initially Sam has 4700 and Isaac has 5000 votes

more than half of the 1000 votes yet to be counted go to sam

therefore adding 50% of 1000 to his score gives us

5200

atleast 20% go to isaac this also leaves him at 5200

there are 30% of the votes left i.e. 300 votes

isaac can not with by 300 votes since sam has MORE THAN50% of votes

so d is incorrect

the rest are all plausable i think...

 

[Riot09]

thanx