O-Level Elementary Math
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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 gal’s 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