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NECO Math Questions Some Teachers Couldn't Solve by Nobody: 10:54am On Jun 28, 2016 |
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 10 Likes 9 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:49am On Jun 28, 2016 |
Where are d math gurus in d house? This's just basic math 7 Likes 2 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Xflint(m): 1:24pm On Jun 28, 2016 |
Wealthgang:i will give it a look |
Re: NECO Math Questions Some Teachers Couldn't Solve by TITOBIGZ(m): 1:29pm On Jun 28, 2016 |
We r coming ![]() ![]() 1 Like |
Re: NECO Math Questions Some Teachers Couldn't Solve by Elxandre(m): 1:31pm On Jun 28, 2016 |
disgraceful! |
Re: NECO Math Questions Some Teachers Couldn't Solve by Mypeople2(m): 3:31pm On Jun 28, 2016 |
7a.)n =0 or 1 7 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Mypeople2(m): 3:36pm On Jun 28, 2016 |
b) x = 1 or 4 3 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Mypeople2(m): 3:44pm On Jun 28, 2016 |
3) The father is 60 years old while the son is 12years 13 Likes 3 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Damfash(m): 4:12pm On Jun 28, 2016 |
(Q3) 60 and 12. (Q7a) n=0 or 1 (Q7b) x=4 or 1 (Q9a) 94 15 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Xflint(m): 4:24pm On Jun 28, 2016 |
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 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 [s][/s] 76 Likes 3 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Xflint(m): 5:56pm On Jun 28, 2016 |
32n+1 - 4(3n+1) + 9 = 0 Note that 32n+1 = 31.32n = 31.(3n)2 while 4(3n+1) = 4(31.3n) Now 3(3n)2 - 4 x 3(3n) + 9 = 0 3(3n)2 - 12(3n) + 9 = 0 Let us call 3n = y therefore 3y2 - 12y + 9 = 0 Divide by 3 we will have y2 - 4y + 3 = 0 y2 - 3y - y + 3 = 0 (y2 - 3y)(-y +3) y(y - 3) - 1(y - 3) (y - 1)(y - 3) y=1 or 3 therefore when y=1 3n = y n = 0 when y = 3 3n = y n = 1 n= 0 or 1 Answer 130 Likes 7 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 7:32pm On Jun 28, 2016 |
Too many critics, so I had to remove the thread. All the same, I HAVE LEARNT THE RIGHT WAY OF DOING IT. Thanks! 9 Likes 1 Share |
Re: NECO Math Questions Some Teachers Couldn't Solve by essay123(m): 8:40pm On Jun 28, 2016 |
Laive: 5x^2-20x-4x+16=448 10 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by integritylady(f): 8:51pm On Jun 28, 2016 |
Wealthgang: will try harder next time ![]() |
Re: NECO Math Questions Some Teachers Couldn't Solve by Damfash(m): 9:44pm On Jun 28, 2016 |
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) into 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 6 Likes 2 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 9:47pm On Jun 28, 2016 |
essay123:Yeah...that's VERY true Essay123! Thanks for the correction. 2 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 10:10pm On Jun 28, 2016 |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 10:11pm On Jun 28, 2016 |
Elxandre:Na so we see am o... Remember dat teacher in Edo who couldn't read well? 1 Like |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 10:19pm On Jun 28, 2016 |
Mypeople2: Mypeople2: Mypeople2: Nailed it. Respek Boss! 7 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 10:41pm On Jun 28, 2016 |
Xflint: Xflint: A casket for these two questns. They've been murdered ![]() Respek boss! Tnx 4 showing d working too. 19 Likes 2 Shares |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:01pm On Jun 28, 2016 |
Laive:Splendid! Laive: Four years ago, d father was (5x-4)yrs while d son was (x-4)yrs old The product of their ages 4yrs ago equaled 448. => (5x-4)(x-4) = 448 5x2 - 24x + 16 = 448 5x2 - 24x - 432 = 0 This quadratic equation has d solution to d problem ![]() 7 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Elxandre(m): 11:03pm On Jun 28, 2016 |
essay123:I stopped solving this thing at this point. Just couldn't bother to factorize Or find any roots ![]() 2 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:03pm On Jun 28, 2016 |
Wealthgang:Where are his workings pls ![]() |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:03pm On Jun 28, 2016 |
integritylady: I know u can solve it. Seen some of ur handwork |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:06pm On Jun 28, 2016 |
Mypeople2:pls Mypeople2, show us some workings... |
Re: NECO Math Questions Some Teachers Couldn't Solve by Elxandre(m): 11:09pm On Jun 28, 2016 |
Wealthgang:My friend, complete your solvings. ![]() 1 Like |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:12pm On Jun 28, 2016 |
Wealthgang:Ok! Learnt something new! But the quadratic equation does not say much about their present ages. Why? 1 Like |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:13pm On Jun 28, 2016 |
Elxandre: ![]() @Mypeople. No workings Sir ![]() |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 11:14pm On Jun 28, 2016 |
Re: NECO Math Questions Some Teachers Couldn't Solve by Mypeople2(m): 11:46pm On Jun 28, 2016 |
Wealthgang:After this, use quadratic equation general formular [ -b +_ √(b^2-4ac)]/2a.You are going to get .X = 12 or -7.2.Disregard the negative value of x since someone's age cannot be negative. So the son's age(x) is 12 .Remember the father's age is 5x....so 5 times 12 = 60.Therefore the father is 60 years old while the son is 12 years old 10 Likes |
Re: NECO Math Questions Some Teachers Couldn't Solve by Nobody: 12:24am On Jun 29, 2016 |
Laive: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 24 Likes 3 Shares |
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