Stats: 3,191,463 members, 7,944,301 topics. Date: Monday, 09 September 2024 at 02:09 PM |
Nairaland Forum / Nairaland / General / Education / Algebra Cafe: Solve Math Problems Here (18256 Views)
If You Can Solve These Math Problems, You Are One Of The World's Smartest / If You Can Solve These Math Problems, You Are One Of The World's Smartest / 10 Year Old Nigerian Math Genius, Esther Okade Plans To Build A Bank By Age 15 (2) (3) (4)
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (Reply) (Go Down)
Algebra Cafe: Solve Math Problems Here by kobe(m): 7:38pm On Mar 29, 2008 |
Forget the meaning of life--the real search is for the value of x! Basic Algbebra: A number has two digits. When the two digits that make up the number are added, their sum is 15. When the number is reversed ( for example 12 becomes 21), the new number is 9 more than the initial number. What is the number? Provide mathematical details of your answer. cheers ![]() |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:48pm On Mar 29, 2008 |
A boy is three years younger than his sister. If his age three years ago was two-thirds her age at that time, what are their present ages? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 8:13pm On Mar 29, 2008 |
Solve this equation: Solve: sqrt(x-4) + 10 = sqrt(x+4) |
Re: Algebra Cafe: Solve Math Problems Here by drrionelli(m): 10:06pm On Mar 30, 2008 |
The answer to the first question is 78 and 87. 87-78=9 8+7 or 7+8 equals 15 |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 11:22pm On Mar 30, 2008 |
Let x be the first digit and y the second digit of the first number. Thus the first number could be written xy. Since this is a two digit number it is actually composed thus; xy => 10x + y When the digits are reversed, we get the number yx, which really translates to; yx => 10y +x The sum of the digits of the first number is 15, thus x + y = 15 ------------------------------------------- (1) The second number is 9 more than the first, thus 10x + y + 9 = 10y + x, which reduces to x - y = -1 --------------------------------------------------- (2) So we have two equations, (1) and (2) From whence x = 7 and y = 8. So the first number is 78. QED 1 Like |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 11:29pm On Mar 30, 2008 |
Excellent answer Huxley . . . i just couldnt figure out how to work with the "two digit number" information. |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 11:30pm On Mar 30, 2008 |
sqrt(x-4) + 10 = sqrt(x+4) Square both sides; (x-4) +20sqrt(x-4) +100 = (x+4) 20sqrt(x-4) = -92 x = (-92/20)^2 + 4 |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 11:32pm On Mar 30, 2008 |
kobe: Let sisters age now = a boy's age now = a - 3 3 yrs ago Sisters age = a - 3 boy's age = (a - 3) - 3 = a - 6 therefore (a - 6) = 2/3(a - 3) Solving equations for a . . . sister's age now = 12, brother's age now = 9. |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 11:39pm On Mar 30, 2008 |
kobe: I expected the answer would be a round figure. Arrived at the same answer as Huxley . . . |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 11:45pm On Mar 30, 2008 |
4Him: Thanks for the compliments. I remembers setting a similar problems to a class of students learning mathematical modelling some years ago. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 5:46am On Mar 31, 2008 |
Wow good job guys. you've certainly more than met expectations, way to go. I'll post more below. Enjoy ![]() |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 6:29am On Mar 31, 2008 |
A special lottery is to be held to select the student who will live in the only deluxe room in a dormitory. There are 100 seniors, 150 juniors, and 200 sophomores who applied. Each senior's name is placed in the lottery 3 times; each junior's name, 2 times; and each sophomore's name, 1 time. What is the probability that a senior's name will be chosen? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 6:47am On Mar 31, 2008 |
A number P is divisible by 2, 3, and 15. Find a number P, such that P + 30 is also divisible by 2, 3, and 15. Show your work. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 6:52am On Mar 31, 2008 |
Of the 6 courses offered by the music department at her college, Kay must choose exactly 2 of them. How many different combinations of 2 courses are possible for Kay if there are no restrictions on which 2 courses she can choose? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 6:58am On Mar 31, 2008 |
Let the function f be defined by f(x) = x2 - 7x + 10 and f(t + 1) = 0, what is one possible value of t? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 10:35am On Mar 31, 2008 |
If the positive integer y leaves a remainder of 2 when divided by 8, what will the remainder be when y + 9 is divided by 8? |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 5:45pm On Mar 31, 2008 |
kobe: y = 8n + 2 so, if we add 6 to y, it will make it a multiple of 8. So we are left with a 3. So the remainder is 3. |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 6:00pm On Mar 31, 2008 |
kobe: t = 4 or 1 (t+1)2 -7(t+1) +10 = 0 t2 - 5t + 4 = 0 (t-1)(t-4) = 0 whence t = 1 or t = 4 QED |
Re: Algebra Cafe: Solve Math Problems Here by huxley(m): 6:05pm On Mar 31, 2008 |
kobe: I don't think this one is very well defined. In fact, P can be any multiple of 30, thus 30, 60, 90, 120, , |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 7:49pm On Mar 31, 2008 |
kobe: this is tough . . . dont have a good background in statistics but i think the answer is 5/18 Anyone solved it yet? |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 7:53pm On Mar 31, 2008 |
kobe: i think this is 6 P 2 = 30 |
Re: Algebra Cafe: Solve Math Problems Here by donchichi: 8:05pm On Mar 31, 2008 |
kobe: let me try. There are 100 seniors each with three opportunities. that makes a total of 300 opportunities. same goes for the sophomores and juniors bring it to a total of 800 opportunities. So, probablity that a senior will be chosen is number of senior opportunities diviided by total number of opportunities. which is 300/800 or 3/8 i hope we r not doing your assignment for u ![]() |
Re: Algebra Cafe: Solve Math Problems Here by 4Him(m): 8:09pm On Mar 31, 2008 |
donchichi: Your answer is the correct one. |
Re: Algebra Cafe: Solve Math Problems Here by dinozzo(m): 8:22pm On Mar 31, 2008 |
kobe:I think its 3/8, been a while though so I'm not sure. Since there are 100 seniors and each seniors name entered 3 times so thats 300 entries, 150 juniors entered twice thats another 300 entries then sopohomore's once that makes 800 entries in all, 300 of which are seniors. So probability will be 300/800 which will be 3/8. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 5:12am On Apr 01, 2008 |
4Him: should be 15. woohoo, you guys are getting them all right. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:22am On Apr 01, 2008 |
How many liters of a 10% solution of acid should be added to 20 liters of a 60% solution of acid to obtain a 50% solution? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:27am On Apr 01, 2008 |
I have $11.60, all dimes and quarters, in my pocket. I have 32 more dimes than quarters. How many dimes, and how many quarters, do I have? For non-Americans, a dime is $0.10 and a quarter is $0.25. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:30am On Apr 01, 2008 |
I was able to balance a weightless beam, ten meters long, on a fulcrum by putting a 6 kg mass on one end, and an unknown mass on the other end. To balance this, I had to place the fulcrum 1.5 meters from the 6kg mass. What is the unknown mass? |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:31am On Apr 01, 2008 |
Rasheed can mow his mother's lawn in 6 minutes. His brother Peter can mow it in 9 minutes. How long will it take them to do it together, if each has his own lawnmower. |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 7:52am On Apr 01, 2008 |
The following is invalid, explain why. a = x a+a = a+x 2a = a+x 2a-2x = a+x-2x 2(a-x) = a+x-2x 2(a-x) = a-x 2 = 1 |
Re: Algebra Cafe: Solve Math Problems Here by donchichi: 8:09am On Apr 01, 2008 |
kobe: if we reverse the eqn from the start; x = a x+x = x+a 2x = x+a Now referring to your equation at exactly 2a-2x = a+x-2x if we substititute the value fro 2x on the RHS, we get a+x-(x+a) which gives 0 the 2x in the equation is a not a single entity but a sum of two entities |
Re: Algebra Cafe: Solve Math Problems Here by kobe(m): 8:23am On Apr 01, 2008 |
I see what you're getting at but that's not qutie the problem. The statement is a valid one. donchichi: |
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (Reply)
2012/ 2013 Waec Gce Registration / The Federal Polytechnic Ado Ekiti 2013/2014 Admission / 10 Types Of Boarding School Students
(Go Up)
Sections: politics (1) business autos (1) jobs (1) career education (1) romance computers phones travel sports fashion health religion celebs tv-movies music-radio literature webmasters programming techmarket Links: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) Nairaland - Copyright © 2005 - 2024 Oluwaseun Osewa. All rights reserved. See How To Advertise. 54 |