O-Level Elementary Math
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can someone help me solve this sec 3 math problem
There is a 2 digit no. such that the sum of its digit is 6 while the product of the digits is 1/3 the original no. Find this no. (Hint: Let x be one of the digits)
thks -
wei lun:
sum = 6 means only the following number pairs are possible :can someone help me solve this sec 3 math problem
There is a 2 digit no. such that the sum of its digit is 6 while the product of the digits is 1/3 the original no. Find this no. (Hint: Let x be one of the digits)
thks
1 5
2 4
3 3
4 2
5 1
and 1/3 of the original numbers are : 5, 8, 11, 14, 17
product of the digits are : 5, 8, 9, 8, 5
the answer is obvious, this is NMOS question ? -
thks for your reply but need to use equation to solve this problem.
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wei lun:
thks for your reply but need to use equation to solve this problem.
Hi wel lun,
Here you go:
Let the first digit be x,
Since the sum of the digits is 6, the second digit would be 6-x,
Therefore, the products of the digits would be = x(6-x)
= 6x-x^2
If the first digit is x, and it is a 2 digit number, x must be in the tens place, hence the NUMERICAL value of x would be = 10 x (x)
= 10x
Since the second digit is in the ones place, the NUMERICAL value of 6-x would be
= 1 x (6-x)
= 6-x
Hence, the NUMERICAL value of the 2 digit number would be = 10x + (6-x)
= 10x + 6 - x
= 9x +6
Since the products of the digits IS EQUAL to the 1/3 of the original number, we can construct the equation as follows,
6x-x^2 = (1/3) x (9x+6)
Rearranging the equation, we will have,
6x-x^2 = 3x+2
6x = x^2+3x+2
0 = x^2+3x-6x+2
0 = x^2-3x+2
x^2-3x+2 = 0
Factorising using the Cross technique you learnt in secondary 2,
You will get,
(x-2)(x-1)=0
x=2 or x=1 (first digit)
6-x=4 or x=5 (second digit)
Hence, the original number may be 24 or 15.
SOLVED! =D :imcool:
You may call me at 92220737 if you require any further assistance in these maths questions, I will be glad to help! -
Can someone pls enlighten me the following maths qn as I am really clueless when come to my galโs Secondary maths qn. Thanks
Find the value of X
2 logx 4 - 3 log4 X = 1 -
savoury sweet:
first change log base x to log base 4, ieCan someone pls enlighten me the following maths qn as I am really clueless when come to my gal's Secondary maths qn. Thanks
Find the value of X
2 logx 4 - 3 log4 X = 1
logx 4=(log4 4) /(log4 x) = 1/(log4 x)
let y= log4 x
hence eqn becomes 2[1/y] - 3y =1
or 2 - 3y^2 = y
or 3y^2 + y -2 =0
(3y-2)(y+1)=0
hence y=2/3, or y=-1
log4 x= 2/3 --> x=4^(2/3)
or log4 x =-1 --> x=4^(-1) -
Thank you so much mum_sugoku. Will show my gal today
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Angle BOC = 64 x 2 = 128 degrees (because angle at the centre is 2x angle at the circumference)
Triangle BOC is isoceles. So that means angle OCB = angle OBC = (180 - 128)/2 = 26 degrees.
Angle AOC = 180 - 16 - 26 = 138 degrees.
Angle DOC = 180 - 138 = 42 degrees
Triangle OCD is isoceles. So that means angle OCD = angle DOC = (180-42)/2 = 69 degrees.
Angle ADB = 69-64 = 5 degrees.
Angle ABD = 180 - 5 - 16 = 159 degrees.
Angle DBC = 180 - 159 = 21 degrees. -
Hi,
I need help for the following questions
1)
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part d.
My answers for part a,b,c:
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2)
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3)
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4)
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5)
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Part iv
My answers for i,ii,iii:
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6)
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Thank you!! -
Can someone help me with this maths question?
Factorise 144z^2 + 121. -
Goodluck889:
It can't be factorise unless it is a minus(-) signCan someone help me with this maths question?
Factorise 144z^2 + 121. -
Goodluck889:
This has a pair of complex roots. So, it isCan someone help me with this maths question?
Factorise 144z^2 + 121.
(z + 11/12 i)(z - 11/12i), where i = sqrt(-1) is the imaginary number.
This is not in the O level syllabus, only in the A level syllabus. -
How to solve this compound interest problem!
A man deposited 2,000 into a bank that paid compound interest of 3.28% compound half yearly. He continued depositing $2,000 into the bank every six months.Calculate the amount of money he had after he made his fifth deposit of $2,000,giving your answer correct to the nearest cent.
I need help to solve this question in an easy way acceptable for O level. Also I have a doubt about whether the interest given(3.28%) is annual interest or half year interest as in the question,it is not mentioned clearly.
Thanks -
Can help me with this math question?
The result โlg xy = lg x + lg yโ is not always true!
1a) Give a pair of values of x and y such that the result will not hold.
Similarly, give values of x,y and r such that the following results fail:
1b) lg x/y = lg x - lg y
1c) lg x^r = r lg x
I understand the condition that x and y must be positive number for lg to be defined and r must be real number.
can you tell me how to answer the above question.
Thank you -
Can someone help me with this question?
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thank you -
Volcano123:
Can someone help me with this question?
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thank youhttp://i58.tinypic.com/nno1mv.png\">
Answer for
Part i) is 2 + 2โ2 and Part ii) is 2 ยฑ 2โ2 -
Dear jieheng,
Thank you very much for your help greatly. -
Thank you very much Jieheng for your help .
part i is only the positive answer bcos log of -ve number is undefined.
part ii has both the positive and negative answer.
Thank you once again. You are marvelous. -
Volcano123:
Hi Volcano123 'Thank you very much Jieheng for your help .
part i is only the positive answer bcos log of -ve number is undefined.
part ii has both the positive and negative answer.
Thank you once again. You are marvelous.
You are right .
The working for both parts i) and ii) are the same but the negative answer for part i) should be rejected due to logโ x -
student101:
It is rather ambiguous, I'm leaning towards the interest as per annum, otherwise they might as well word it such that the deposits are made every year and ask the for the amount after the 5th year.How to solve this compound interest problem!
A man deposited 2,000 into a bank that paid compound interest of 3.28% compound half yearly. He continued depositing $2,000 into the bank every six months.Calculate the amount of money he had after he made his fifth deposit of $2,000,giving your answer correct to the nearest cent.
I need help to solve this question in an easy way acceptable for O level. Also I have a doubt about whether the interest given(3.28%) is annual interest or half year interest as in the question,it is not mentioned clearly.
Thanks
Breaking down the timeline might be the easiest way to explain to a student.
After 1st deposit : 2000
After 2nd deposit : 2000 x 1.0164 + 2000 = 4032.8
After 3rd deposit : 4032.8 x 1.0164 + 2000 = 6098.9379
After 4th deposit : 6098.9379 x 1.0164 + 2000= 8198.961
After 5th deposit : 8198.961 x 1.0164 + 2000= 10333.42