ATOT Maths Challenge

JJChicken

Diamond Member
Apr 9, 2007
6,165
16
81
Back in the 10th grade I undertook a a highly prestigous mathematics challenge in which I got full marks by answering 16 questions over a few months. I will post the questions one at a time, with each question being posted when the previous question has been answered. There's many ways in answering these questions, but it is unlikely that google will be of much use (sorry :p). Let's see how good ATOT is at higher maths. The questions vary in difficulty.
If everyone is stuck, I will try to find where I wrote down my answers, although I'm not too sure I still have them (its been quite a few years)

By the way, the questions are worded perfectly, they were written up by genius mathematicians and is sponsored by the education department.

Without further adeu, here is the first question.

Problem 1
The distance between villages A and B is 65km. Three backpackers, Lisa, Mary and Nora, who are at A, want to get to B. They have a motorbike able to carry up to two people at a constant speed of 50 km/h and each of the backpackers can walk at a constant speed of 5 km/h. They all started their journey at 8am: Lisa and Mary went on the bike while Nora walked. After a certain time, Mary got off the bike and continued her trip on foot. Lisa immediately turned back and after picking up Nora turned towards B again and started riding without losing any time. All three of them arrived at B at the same time. When did they arrive at B?


EDIT:
Problem 1 has been solved!

The next one should be easy, a few of the last ones will be VERY challenging.

Problem 2
Find all positive integers N such that 32N + 97 is divisibe by 4N - 1.

EDITX2:
Problem 2 has been solved!

Problem 3
Simplify
{[x^2 + 6xy + 9y^2]/[x^2 - 9y^2]}/{[x^2 + 3xy - 2x - 6y]/[x^3 - 3yx^2 - 4x + 12y]}
 

Demon-Xanth

Lifer
Feb 15, 2000
20,551
2
81
This is your homework, isn't it?

...oh, and Mary got mauled by a mountain lion while Lisa found Nora being eaten by a bear. At which point a serial killer kidnapped her in a white van and she hasn't been seen since. The moral of the story is don't get a scooter, get a car. If they had a car they'd all be alive still. You really need to consider your personal safety in these matters.
 

JJChicken

Diamond Member
Apr 9, 2007
6,165
16
81
Originally posted by: Demon-Xanth
This is your homework, isn't it?

...oh, and Mary got mauled by a mountain lion while Lisa found Nora being eaten by a bear. At which point a serial killer kidnapped her in a white van and she hasn't been seen since. The moral of the story is don't get a scooter, get a car. If they had a car they'd all be alive still. You really need to consider your personal safety in these matters.

lol nah I'm graduating from uni this year :)

I think the moral is IhaveCandyGetintheVan ;)

Maybe these questions are too difficult for ATOT?
 
Dec 26, 2007
11,782
2
76
Originally posted by: Demon-Xanth
This is your homework, isn't it?

...oh, and Mary got mauled by a mountain lion while Lisa found Nora being eaten by a bear. At which point a serial killer kidnapped her in a white van and she hasn't been seen since. The moral of the story is don't get a scooter, get a car. If they had a car they'd all be alive still. You really need to consider your personal safety in these matters.

Oh and they would have all arrived there at 9:18
 

JJChicken

Diamond Member
Apr 9, 2007
6,165
16
81
Damn I just re-solved (after 8 years) the question in my head within 30 seconds. C'mon ATOT this one is probably one of the easiest of the 16.
 

ivan2

Diamond Member
Mar 6, 2000
5,772
0
0
www.heatware.com
takes 2.945 hours pass 8, so I will say about 10:56AM

don't ask me for work cuz know the answer is right.

the girl who walked first on foot travelled 9.14 KM and the girl who got off the bike traveled 14.73 KM. plug them in to verify.
 

Mr Pickles

Diamond Member
Feb 24, 2006
4,103
1
0
Lisa, Mary, and Nora never make it. They find themselves lonely, start experimenting, realize that if they reach their destination they'll be outcasts, and decided to live as carpet lickers in the woods (as ironic of a pun that may be).
 

CraKaJaX

Lifer
Dec 26, 2004
11,905
148
101
Originally posted by: Mr Pickles
Lisa, Mary, and Nora never make it. They find themselves lonely, start experimenting, climaxed 19 times and realize that if they reach their destination they'll be outcasts, and decided to live as carpet lickers in the woods (as ironic of a pun that may be).

Fixed.
 

cubby1223

Lifer
May 24, 2004
13,518
42
86
Originally posted by: Barack Obama
Problem 1
The distance between villages A and B is 65km. Three backpackers, Lisa, Mary and Nora, who are at A, want to get to B. They have a motorbike able to carry up to two people at a constant speed of 50 km/h and each of the backpackers can walk at a constant speed of 5 km/h. They all started their journey at 8am: Lisa and Mary went on the bike while Nora walked. After a certain time, Mary got off the bike and continued her trip on foot. Lisa immediately turned back and after picking up Nora turned towards B again and started riding without losing any time. All three of them arrived at B at the same time. When did they arrive at B?

What are these kilometers you speak of? :p
 

cubby1223

Lifer
May 24, 2004
13,518
42
86
x=distance when the first walker was picked up
y=distance when the biker began walking

65-x=y
x @ 5kmph + y @ 50kmph = (2y+(65-2x)) @ 50kmph

whoever wants to work it out, I don't care. Only thing I'd like to know is, the motorbike always runs at a constant 50kmph, must have been rough when the one was shoved off the bike at such high velocity. ;)



edit - I'm failing to see how this is considered "higher" math. :confused:
 

BoomerD

No Lifer
Feb 26, 2006
66,280
14,702
146
Maths? hmmm...2+2=? ummm...waidaminit...I know this one...hold on, let me take off my shoes so I kin kount...6! That's it...6!
 

sdifox

No Lifer
Sep 30, 2005
100,312
17,907
126
Originally posted by: cubby1223
x=distance when the first walker was picked up
y=distance when the biker began walking

65-x=y
x @ 5kmph + y @ 50kmph = (2y+(65-2x)) @ 50kmph

whoever wants to work it out, I don't care. Only thing I'd like to know is, the motorbike always runs at a constant 50kmph, must have been rough when the one was shoved off the bike at such high velocity. ;)



edit - I'm failing to see how this is considered "higher" math. :confused:

I don't think your understanding is right... the biker doubles back to pick up the walker so x+y<65


this is how it looks

a=Distance traveled by Lisa and Mary on bike
b=Distance traveled by Nora on bike (and Lisa too)
c=Distance traveled by Nora on foot
d=Distance traveled by Lisa on bike on her way back to pick up Nora
e=Distance traveled by Mary on foot

a+e=65
c+b=65
a+b-d=65


a/50+d/50+b/50=a/50+e/5=c/5+b/50