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NECO Math Questions Some Teachers Couldn't Solve - Education (3) - Nairaland

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Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:15am On Jun 29, 2016
1(3[/sup]2n+1)-4(3[sup]n+1) +9=0

1-4(3[/sup]2n+1-n-1)+9=0

-3(3[sup]
n)+9=0
-9[/sup]n+9=0

-9[sup]
n=-9
or 9[sup][/sup]n=9 ie taking - to the other side
n=1
Re: NECO Math Questions Some Teachers Couldn't Solve by Xflint(m): 9:17am On Jun 29, 2016
leahcimzil:
lol but this ain't Maths nah...I used to think i knew maths until i got into the Uni and started doing, Abstract Algebra and Advanced Calculus

Maybe you can help teach some of us more especially myself. I am always ready to learn
Re: NECO Math Questions Some Teachers Couldn't Solve by goody1shoe73(m): 9:18am On Jun 29, 2016
Laive:

Let me try one Question at a time.
Solution
Let the son's age be:
.
x
.
Therefore, father's age:
.
5x
.
Four years ago, if we multiply their ages, we would get:
.
5x = 448
.
From here, the son's age becomes:
.
x = 448/5
x = 89.6

.
Therefore, 4 year ago, son's age was:
.
89.6
.
4 years have passed, we'll add extra 4 years to the son's age:
.
89.6 + 4 = 93.6
.
Therefore, his son is currently 93.6 years old (more like 93years and 6 months).
.
From the question, we were told that the man is 5 times older than his son.
.
Therefore, we will multiply the son's age by 5 to get the man's age 4 years ago:
.
5 x 93.6 = 448
.
The man was 448 years in the last 4 years.
.
4 years have passed, his present age will be:
448 + 4 = 452
.
Op
Na Methuselah gene dem carry?
Re: NECO Math Questions Some Teachers Couldn't Solve by Kaybee7000(m): 9:19am On Jun 29, 2016

Re: NECO Math Questions Some Teachers Couldn't Solve by boss096(m): 9:20am On Jun 29, 2016
Xflint:
7b) solution

Log(x2 + 4) = 2 + logx - log20
log(x2 + 4) = log100 + logx - log20
log(x2 + 4) = log (100 X x/20)

Now, you cross multiply
given you 20(x2 + 4) = 100 X x
20x2 + 80 = 100x

now divid by 20
[strike]20[/strike]x2/[strike]20[/strike] - [strike]100[/strike]x/[strike]20[/strike] + 80/[strike]20[/strike] = 0

x2 - 5x + 4 = 0
x2 - 4x - x + 4 = 0
(x2 - 4x)(x + 4)
x(x - 4) -1(x - 4)
(x - 1)(x - 4)
x = 1 or 4

the strike is not working here just check
http://forum.mathsboard.com/t594-solve-this-neco-past-questions-2016-2017#1517
your log sucks!
Re: NECO Math Questions Some Teachers Couldn't Solve by ENIGMA24(m): 9:21am On Jun 29, 2016
Some people are talking about how maths is irrelevant to the society, if you were wise you would understand all economic and financial projections are usually mathematical (more econmoic tho, but whats economic analysis without maths? ) ..... Security issues are very mathematical, find out from the soldiers who calculate rocket projectile and launching speed.....
Maths is relevant, atleast if not for any major reason u need to pass maths in waec or neco to forge ahead academically else u get stuck and join the nigerian police force with your o'level .. ... U pefer to collect #20?

2 Likes

Re: NECO Math Questions Some Teachers Couldn't Solve by heskeyw(m): 9:22am On Jun 29, 2016
I studied marketing bt I will gv it a shot.
Solving
A man is 5 times older than his son
Mathematically
Let d son's age be x.
Papa age (since he's 5times older) = 5timesx which is 5x.

Four yrs ago, d product of their ages was 448
Mathematically
X times 5x = 448
»5x2(square) = 448.
X2 =448/5
X2= 89.6
X = square root of 89.6 which is 9.46
Therefore, the son's age is 9.46yrs while the papa is 9.47 times 5 which is 47.35yrs.

Ka odi banu.
Re: NECO Math Questions Some Teachers Couldn't Solve by Xflint(m): 9:22am On Jun 29, 2016
boss096:
your log sucks!
that was hw could go about it. Different formula for a single maths
pls can you teach me another formula to use I am open minded.
Thanks
Re: NECO Math Questions Some Teachers Couldn't Solve by mfm04622: 9:23am On Jun 29, 2016
Laive:

Let me try one Question at a time.
Solution
Let the son's age be:
.
x
.
Therefore, father's age:
.
5x
.
Four years ago, if we multiply their ages, we would get:
.
5x = 448
.
From here, the son's age becomes:
.
x = 448/5
x = 89.6

.
Therefore, 4 year ago, son's age was:
.
89.6
.
4 years have passed, we'll add extra 4 years to the son's age:
.
89.6 + 4 = 93.6
.
Therefore, his son is currently 93.6 years old (more like 93years and 6 months).
.
From the question, we were told that the man is 5 times older than his son.
.
Therefore, we will multiply the son's age by 5 to get the man's age 4 years ago:
.
5 x 93.6 = 448
.
The man was 448 years in the last 4 years.
.
4 years have passed, his present age will be:
448 + 4 = 452
.
Op

Very wrong.
Re: NECO Math Questions Some Teachers Couldn't Solve by InfomejobsN: 9:27am On Jun 29, 2016
Which School Teachers Couldn't Solve this?



Check My Signature for Daily Job Info
Re: NECO Math Questions Some Teachers Couldn't Solve by mfm04622: 9:27am On Jun 29, 2016
BLoomfrancs:


Guy you no dey shame to post this rubbish here. People are talking about building robots that can fight in battles like ground soldiers you are here posting nonsense.

If you don't have foundation in mathematics, how can you dream of building ANYTHING? Na you no get shame!

3 Likes

Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:27am On Jun 29, 2016
Laive:

Let me try one Question at a time.
Solution
Let the son's age be:
.
x
.
Therefore, father's age:
.
5x
.
Four years ago, if we multiply their ages, we would get:
.
5x = 448
.
From here, the son's age becomes:
.
x = 448/5
x = 89.6

.
Therefore, 4 year ago, son's age was:
.
89.6
.
4 years have passed, we'll add extra 4 years to the son's age:
.
89.6 + 4 = 93.6
.
Therefore, his son is currently 93.6 years old (more like 93years and 6 months).
.
From the question, we were told that the man is 5 times older than his son.
.
Therefore, we will multiply the son's age by 5 to get the man's age 4 years ago:
.
5 x 93.6 = 448
.
The man was 448 years in the last 4 years.
.
4 years have passed, his present age will be:
448 + 4 = 452
.
Op

sons age = x, Father's age = y
(x-4)(y-4)=448.........(1)
y=5x..........(2)

sub. (2) in (1)
(x-4)(5x-4)=448
5x^2-20x-4x+16=448
5x^2-24x+16=448
5x^2-24x-432=0
5x^2-60x+36x-432=0
5x(x-12)+36(x-12)=0
(5x+36)(x-12)=0
x=-36/5, or x=12
since age can't be a negative fraction;
THE BOY IS 12yo
therefore 12x5=60
THE FATHER IS 60yo

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:27am On Jun 29, 2016
present ages are 13.47 and 51.47
Re: NECO Math Questions Some Teachers Couldn't Solve by dacovajnr: 9:28am On Jun 29, 2016
Find MathChick go undecided
Re: NECO Math Questions Some Teachers Couldn't Solve by cosmic22(m): 9:28am On Jun 29, 2016
calculating for 4 years ago
man-5x
son-x
product of ages
5x * x = 448
5x squared = 448
x squared=448/5
x = √89.6
x = 9.465 ( boys age )
(fathers age) 5x = 47.325
calculating present ages
approximate ages
9 + 4 = 13 years old (boys age) 47 + 4 = 51 years old ( fathers age)
Re: NECO Math Questions Some Teachers Couldn't Solve by CUM4WHAT(m): 9:29am On Jun 29, 2016
Laive:

Let me try one Question at a time.
Solution
Let the son's age be:
.
x
.
Therefore, father's age:
.
5x
.
Four years ago, if we multiply their ages, we would get:
.
5x = 448
.
From here, the son's age becomes:
.
x = 448/5
x = 89.6

.
Therefore, 4 year ago, son's age was:
.
89.6
.
4 years have passed, we'll add extra 4 years to the son's age:
.
89.6 + 4 = 93.6
.
Therefore, his son is currently 93.6 years old (more like 93years and 6 months).
.
From the question, we were told that the man is 5 times older than his son.
.
Therefore, we will multiply the son's age by 5 to get the man's age 4 years ago:
.
5 x 93.6 = 448
.
The man was 448 years in the last 4 years.
.
4 years have passed, his present age will be:
448 + 4 = 452
.
Op
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:32am On Jun 29, 2016
Next story please, I nor like Maths
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:33am On Jun 29, 2016
Horlawale1:
Am a big lover of mathematics, but lately am losing interest. tongue

Sincere question, how can this be use to solve economy situation, or how is this applicable in real life.

While some School Cert holder are discovering new inventions in China, we are here looking for 'X'
Who X help

Nigeria education sector needs review.
My opinion cool

Dude to build a robot you require knowledge in Mechatronics engineering. . . Even common mesh/node analysis requires math, and finding 'x'. Without math all the inventions people are making in other countries would not have existed. Rather, the reform Nigeria needs is to fund practicals and research in universities

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by ENIGMA24(m): 9:33am On Jun 29, 2016
Kaybee7000:
N=3 or 1 Mr man
How can u expand that equation with 3 and 9??
The idle number to expand with is 4 and 3 so when you multiply u can get 12 which is the expanded number!
Re: NECO Math Questions Some Teachers Couldn't Solve by 7thCANON: 9:34am On Jun 29, 2016
Q9a) A two-digit number is such that its tens digit is greater than its unit digit by 5. If d number is 14 less than 3 times d product of its digits, find d number.

Let the two digits be X and Y. This implies that the two-digit number is:
10X+Y ----------------------------eqn 1
its tens digit is greater than its unit digit by 5: this implies –
X = Y + 5 -----------------------eqn 2
If d number is 14 less than 3 times d product of its digits: this implies
(10X + Y ) + 14 = 3XY.-----------------------eqn 3
find d number. By substituting (2) in (3) we and rearranging we have:
3Y^2 + 4Y – 64 = 0
Solving the quadratic equation yields Y = 4 or -16/3. We discard the second value of Y is it is not a whole number. We then solve for X
Ans: X = 9, Y = 4
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:34am On Jun 29, 2016
cosmic22:
calculating for 4 years ago

man-5x

son-x

product of ages

5x * x = 448

5x squared = 448

x squared=448/5

x = √89.6

x = 9.465 ( boys age )

(fathers age) 5x = 47.325

calculating present ages

approximate ages

9 + 4 = 13 years old (boys age)
47 + 4 = 51 years old ( fathers age)
The problem with your solution is that four years ago, the father's age wasn't 5 tines his sons age. its only the CURRENT AGE that is 5 times his son's age

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by Musquareney(m): 9:36am On Jun 29, 2016
Q3) son= 12 and father = 60
Q7a) n= 0 or n= 1
Q7b) x= 1 or x= 4
Q9a) the number is 94
Where are my gifts
Re: NECO Math Questions Some Teachers Couldn't Solve by Edu4g(m): 9:36am On Jun 29, 2016
grin
Elxandre:
disgraceful!
Elxandre:
disgraceful!
Elxandre:
disgraceful!
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:37am On Jun 29, 2016
GeneralShepherd:


Wrong....

Man's age - 5X

Son's age - X

Four years ago the product of their ages (not the son's age) was 448

(x-4) (5x-4) = 448
5x^2 - 24x - 432 =0
Using the quadratic formula

X= 12 or X= -7.199

As we know age cannot be negative so the son's age is 12 years.

The father's age is 60 years
Yeah! I admitted that long before your thread. Thanks for showing me the correct way of solving it. wink
Re: NECO Math Questions Some Teachers Couldn't Solve by Babysho(m): 9:37am On Jun 29, 2016
Wealthgang:

It does. One of d solutions will give u X which is d present age of d boy. The father's present age will simply be 5X.
Lemme solve it:
By factorization,
5x2 - 24x - 432 = 0
5x2 - 60x + 36x - 432 = 0
5x (x - 12) + 36 (x - 12) = 0
(5x + 36)(x -12) = 0
When 5x + 36 = 0, x = -36/5 = -7.2
When x - 12 = 0, x = 12.

Boy's age = 12yrs and not -7.2 since age cannot be negative.
Father's age = 5x = 5 x 12 = 60yrs.

By quadratic eqn general formula, Mypeople2 has handled that.
x = [-b ± √(b2-4ac)]/2a
5x2 - 24x - 432 = ax2 + bx + c
Comparing, a = 5, b = -24, c = -432
x = [-(-24) ± √(-242 - 4 x 5 x -432)]/2 x 5
= [24 ± √9216]/10
= (24 ± 96)/10
= (24 + 96)/10 or (24 - 96)/10
= 12 or -7.2. (Again, discard -7.2)

Now let's check if answers are correct.
Father's 5 times boy's age: 60 = 5 x 12

4years ago,
(60 - 4)(12 - 4) = 56 x 8 = 448



I wish I can 'like' this twice.

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by freemile2ru: 9:43am On Jun 29, 2016
Damfash:
Q9a. I'll try to make the solution very simple. Let the two-digit number be XY. X is the tens digit while Y is the unit digit. X=Y+5........(i). Note: A two-digit number is ten times the tens digit plus the unit digit. E.g 54=(5*10)+4, 63=(6*10)+3. Let's proceed! (10X+Y)+14=3*X*Y. So, we have 10X+Y+14=3XY........(ii). Sub. equation (i) in equation (ii). 10(Y+5)+Y+14=3Y(Y+5)... 10Y+50+Y+14=3Y^2+15Y.... 3Y^2+4Y-64=0. Y=4 or Y=-5.33. Discard the second value. If Y=4, X=Y+5=4+5=9. The two digit number is 94.@ Wealthgang
100% correct

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by Peacefulgold(m): 9:44am On Jun 29, 2016
Mathematics not really my tin shocked

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by stunner7(m): 9:46am On Jun 29, 2016
Wealthgang:
Check Out The Recent NECO Math Questions Some School Teachers Couldn't Solve


Same order they appeared in d question paper.

Q3) A man is 5 times older than his son. Four yrs ago, d product of their ages was 448. Find their present ages.

Q7a) Find d value of n if
32n+1 - 4(3n+1) + 9 = 0

7b) Solve d eqn:
log(x2+4) = 2 + logx - log20

Q9a) A two-digit number is such that its tens digit is greater than its unit digit by 5. If d number is 14 less than 3 times d product of its digits, find d number.

Let's see how many Nairalanders can give it a shot. Anyone who answers correctly will get a reward.

Cc: Xflint, Boyoski09, truth12, themall, Danosaur007, Jerrypolo, 8BitGee, integritylady, Laive, lilmonarch

2 Likes 1 Share

Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:48am On Jun 29, 2016
valarinz:

Ma oga, u no know book oo, lol
I accept. But that's if there is any harm in trying... Thanks.
Re: NECO Math Questions Some Teachers Couldn't Solve by Adex001(m): 9:54am On Jun 29, 2016
Laive:
Too many critics, so I had to remove the thread. All the same, I HAVE LEARNT THE RIGHT WAY OF DOING IT. Thanks!
grin grin grin grin grin grin grin grin grin grin grin grin grin grin grin come and see metuselah!! grin grin grin grin grin cheesy cheesy cheesy
Re: NECO Math Questions Some Teachers Couldn't Solve by stunner7(m): 9:54am On Jun 29, 2016
Wealthgang:
Check Out The Recent NECO Math Questions Some School Teachers Couldn't Solve


Same order they appeared in d question paper.

Q3) A man is 5 times older than his son. Four yrs ago, d product of their ages was 448. Find their present ages.

Q7a) Find d value of n if
32n+1 - 4(3n+1) + 9 = 0

7b) Solve d eqn:
log(x2+4) = 2 + logx - log20

Q9a) A two-digit number is such that its tens digit is greater than its unit digit by 5. If d number is 14 less than 3 times d product of its digits, find d number.

Let's see how many Nairalanders can give it a shot. Anyone who answers correctly will get a reward.

Cc: Xflint, Boyoski09, truth12, themall, Danosaur007, Jerrypolo, 8BitGee, integritylady, Laive, lilmonarch
From my previous attachment. Son age is presently 12 years while Father's age is 60. Four years ago son age is 8 and Father 56. 56 * 8 =448 (solved)

1 Like

Re: NECO Math Questions Some Teachers Couldn't Solve by SEYIOKE: 9:56am On Jun 29, 2016
3a) son's age 12, father 60.
7a) n =0 or n=1
7b) x=1 or 4
9a) two digit number is 94
Wealthgang:
Check Out The Recent NECO Math Questions Some School Teachers Couldn't Solve


Same order they appeared in d question paper.

Q3) A man is 5 times older than his son. Four yrs ago, d product of their ages was 448. Find their present ages.

Q7a) Find d value of n if
32n+1 - 4(3n+1) + 9 = 0

7b) Solve d eqn:
log(x2+4) = 2 + logx - log20

Q9a) A two-digit number is such that its tens digit is greater than its unit digit by 5. If d number is 14 less than 3 times d product of its digits, find d number.

Let's see how many Nairalanders can give it a shot. Anyone who answers correctly will get a reward.

Cc: Xflint, Boyoski09, truth12, themall, Danosaur007, Jerrypolo, 8BitGee, integritylady, Laive, lilmonarch

1 Like

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