Add Math help needed!

[Snowysangel]

Does anybody have the Summer 1997 past papers? Well I really don't understand question number 5 from paper 2. Could someone please explain it to me

 

[Haris Bin Zahid]

Does anybody have the Summer 1997 past papers? Well I really don't understand question number 5 from paper 2. Could someone please explain it to me

Tell me the topic from which it is from or just post the question! I have a Classified Ad. Maths past papers book which has summer 97 questions!

 

[scouserlfc]

Does anybody have the Summer 1997 past papers? Well I really don't understand question number 5 from paper 2. Could someone please explain it to me

Isnt that question already given in your book

 

[Snowysangel]

Tell me the topic from which it is from or just post the question! I have a Classified Ad. Maths past papers book which has summer 97 questions!

Its in topic 7: logarithmic functions, and is question number 24 (a) in the classified past papers' book from 1996 to 2008

 

[Haris Bin Zahid]

Its in topic 7: logarithmic functions, and is question number 24 (a) in the classified past papers' book from 1996 to 2008

Is this the question: (i) lg x + lg[5(x+1)] = 2
(ii) 3^(y+1)=0.45

 

[Haris Bin Zahid]

Is this the question: (i) lg x + lg[5(x+1)] = 2
(ii) 3^(y+1)=0.45

If yes, then here's the solution:
(i) lg x + lg (5x + 5) = 2
lg x + lg (5x + 5) = lg 10^2
Using the Product law, we have: lg (5x^2 +5x) = lg 100
So, 5x^2 +5x = 100
Now you'll get two solutions. Choose the one value for the which the logarithm is defined. The answer should be x=4.

(ii) 3^(y+1) = 0.45
lg 3^(y+1) = lg 0.45
y+1 = lg 0.45/lg 3
y+1 = -0.73
y = -1.73

 

[Snowysangel]

Is this the question: (i) lg x + lg[5(x+1)] = 2
(ii) 3^(y+1)=0.45

No no. That's part b! I don't get part a. Here's the question:
An object is heated in an oven until it reaches a temperature of X degrees Celsius. It is then allowed to cool. Its temperaure, (theta) degrees celsius, when it has been cooling for t minutes, is givwen by the equation (theta)= 18 + 62 e^-t/x
Find
ii) the value of X
ii) the value of (theta when t = 16
iii) the value of t when (theta)= 48
1v) the rate which (theta) is decreasing when t= 16

I don't understand why there's an x under t as the exponent, and according to the marking scheme of part ii, the value of that x is equal to 8 whereas no part of the question gives that away. The answer to part i is 80 degrees celsius and that, i get how. What particularly confuses me is the presence of the two Xs

 

[Haris Bin Zahid]

No no. That's part b! I don't get part a. Here's the question:
An object is heated in an oven until it reaches a temperature of X degrees Celsius. It is then allowed to cool. Its temperaure, (theta) degrees celsius, when it has been cooling for t minutes, is givwen by the equation (theta)= 18 + 62 e^-t/x
Find
ii) the value of X
ii) the value of (theta when t = 16
iii) the value of t when (theta)= 48
1v) the rate which (theta) is decreasing when t= 16

I don't understand why there's an x under t as the exponent, and according to the marking scheme of part ii, the value of that x is equal to 8 whereas no part of the question gives that away. The answer to part i is 80 degrees celsius and that, i get how. What particularly confuses me is the presence of the two Xs

Nah, you noted the wrong question.
The equation is: 18 + 62 e^-t/8
There's some sort of misprinting.....Check question number 19 in Miscellaneous Exercise 3 in "New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong! It states the correct question.
By the way from where did u get the Marking Scheme of 1997??????????

 

[Snowysangel]

Nah, you noted the wrong question.
The equation is: 18 + 62 e^-t/8
There's some sort of misprinting.....Check question number 19 in Miscellaneous Exercise 3 in "New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong! It states the correct question.
By the way from where did u get the Marking Scheme of 1997??????????

Haha oh i have the past papers book with questions ranging from the year 1996 to 2006
Listen i'm struggling with the chapter on vectors (in math), not that i've done it in school or anything. So, um, f the following is a question taken from the unit;
Three non-collinear points, A, B and C have position vectors a, b and 6a respectively relative to O. P is a point on BC such that BP : PC = 2:1 and T is the midpoint of AP (no diagram has been given)
then how can -OB (or BO) equal to 2OP?? According to its given solution, such is the case, so yeah. I tried drawing it out, but i still don't get it also, there's another question with a similar case so i think i'm missing out on something important

 

[Haris Bin Zahid]

Snowysangel and scouserlfc: Your help needed in this question.
Given that n(E)=23, n(A ∩ B)=x, n(A)=y, n(B)=2y and n(A' ∩ B')=7, find the least possible value of y. The answer is 6. How to do it????
Note: n(E) is for the universal set.

 

[scouserlfc]

Snowysangel and scouserlfc: Your help needed in this question.
Given that n(E)=23, n(A ∩ B)=x, n(A)=y, n(B)=2y and n(A' ∩ B')=7, find the least possible value of y. The answer is 6. How to do it????

I hate sets,Inshaallah will solve tomorrow if no one else touches it

 

[scouserlfc]

I hate sets,Inshaallah will solve tomorrow if no one else touches it

Is this question from the book man because i cant this thing right now but later when im not on the computer ! if not wait ill try my best

 

[Haris Bin Zahid]

Is this question from the book man because i cant this thing right now but later when im not on the computer ! if not wait ill try my best

Yes, from the book!

 

[Snowysangel]

Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math guess I was wrong
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name

 

[Snowysangel]

Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math guess I was wrong
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name

 

[Snowysangel]

Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math guess I was wrong
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name

 

[Haris Bin Zahid]

Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math guess I was wrong
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name

"New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong

 

[celoth]

Snowysangel and scouserlfc: Your help needed in this question.
Given that n(E)=23, n(A ∩ B)=x, n(A)=y, n(B)=2y and n(A' ∩ B')=7, find the least possible value of y. The answer is 6. How to do it????
Note: n(E) is for the universal set.

n(AUB)=23-7
n(A)+n(B)-n(A ∩ B)=16
y+2y-x=16
3y=16+x
y = (16+x)/3

to find minimum value of y,
x must be minimum also,
but x=0, y =16/3
and x=1, y=17/3
both y is not integer, so can't be the answer

so, x=2, y=18/3
y=6

 

[scouserlfc]

n(AUB)=23-7
n(A)+n(B)-n(A ∩ B)=16
y+2y-x=16
3y=16+x
y = (16+x)/3

to find minimum value of y,
x must be minimum also,
but x=0, y =16/3
and x=1, y=17/3
both y is not integer, so can't be the answer

so, x=2, y=18/3
y=6

Wait mate but how can u just use values on ur own is this a method ??

 

[celoth]

Wait mate but how can u just use values on ur own is this a method ??

logical thinking....
what is the range of values of n(A ∩ B) ??