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Mensa Mind teaser

on Sun Dec 24 2017, 19:02
First topic message reminder :

1}I know MYG likes a puzzle so specialy for her and everyone else of course.

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?


2}Take 9 from 6, 10 from 9, 50 from 40 and leave 6.

How Come ??


Last edited by Admin on Thu Jan 04 2018, 20:45; edited 1 time in total

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raymyjamie
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 21:29
Blimey O Riley!!!!!!! confused
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 21:31
I think you're pulling my leg.........................................

...............................................or pulling summat LOL Embarassed Laughing
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 21:34
The answer is 31.5 km from a time of 21 minutes of the faster car travel.Ray added a step of calculating the speed in km/min which to two decimal places throws out the answer.


Last edited by myg on Fri Jan 05 2018, 21:46; edited 1 time in total
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 21:38
No mensa place for you tonight MYG. Unless mensa are wrong that is. Wink
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:02
Distance= speed x time both travel the same distance.
slow car 70/60x(t+6) fast car 90/60x t
70xt+420=90xt
20xt=420
t=21 minutes
distance= 90/60 x 21=31.5km
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raymyjamie
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:04
If you look at my equation:-

Car 1                                  Car 2
6 x 1.16 + 1.16 x t   =    1.5 x t

If you work out each side of the equation it is 30.7 both sides of the 'equals' sign.

t  =  20.47
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:09
Our equations are pretty much the same myg, I have converted

the speeds to kpm beforehand, you have done it within your equation.
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:11
I may just have to give you both the answer. Unless you want another bash You are both close, MYG closest.
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raymyjamie
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:27
Apart from tweaking the 'rounding up' of the numbers,

I'm reasonably happy with my working out as it gives

the result of both cars having the same distance travelled.
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:32
I just hope mensa gave the right answer Very Happy
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:44
I can't fault your logic Ray but see no need to decimalise the speeds.
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raymyjamie
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 22:48
Yes, I have to say, as on my first effort, I've over complicated it

by converting to kpm first.

Yours is a much neater solution with no decimals.

I'm a notreet LOL Embarassed Laughing
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 23:05
I will be interested to see Mensa's answer and logic.
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Re: Mensa Mind teaser

on Fri Jan 05 2018, 23:07
No logic just the answer I'm afraid.

A 110 yard long train, travelling at 80 mph, enters a tunnel of half a mile in length.

How many seconds will elapse between the moment the front of the train enters the tunnel and the moment the end of the train clears the tunnel?


Answer:
Reveal answer
25.3125
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 11:03
I take issue with the answer.

Here is my solution:-


Total distance = 1/2mile +110 yards + 100 yards

Total distance = 1760/2 +110 +110 + = 1100 yds

Speed = 80 mph = 80 x 1760 = 140800 yds/hr

Time = distance divided by speed

Time = 1100 / 140800

Time = 0.0078125 hr

Time = 28.125 seconds

Having said that, I am usually wrong LOL Embarassed Laughing
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 12:28
We will wait to see what MYG comes up with. I wasn't brilliant at maths Embarassed Very Happy
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 13:03
You have already given the answer to this train question.The train has to travel 990 yards at 80mph.
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 13:34
Surely 1/2 a mile is 1760/2 = 880 yds.

Plus 2 x 110 = 220 yds

Total = 1100 yds, not 990 yds.

I think I may have got my figures the wrong way round on my original post Embarassed

Speed = Distance x Time

therefore Time = Speed / Distance.

Time = 140,800 / 1100

Time = 128 seconds

You were right to question my answer myg.

I was much better at maths when I was working LOL Laughing
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 13:44
Yes Ray, the tunnel is 880 yards and at the start of the puzzle the back of the train is 110 yards from the tunnel so to clear it travels 110+880 yards.

990x3600/80x 1760=25.3125 seconds
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 14:01
The puzzle reads:-

"How many seconds will elapse between the moment the front of the train enters the tunnel and the moment the end of the train clears the tunnel?"

Now that I think of it, I had an extra train length included in the overall length.

You are correct, the length covered is 990 yds.

Time = 990 / 140800

Time = 0.00703125 hr

Time = 25.3125 seconds
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raymyjamie
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 14:04
I have to say, even though I get things wrong and often, they are hopefully

keeping the few brain cells that I have in good shape.

Thankfully we have your sharp brain to keep me in check myg

We are off for a walk up to Top Lock now, will catch you later.
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 16:13
I'll make it esy this time Very Happy

Some collywobbles are geniunes.
All geniunes have six legs.
Therefore which of the following must be true?
(a) All collywobbles have six legs.
(b) All genuines are collywobbles.
(c) Some collywobbles have six legs.
(d) It can not be determined whether any of the above are true.
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raymyjamie
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 17:24
Lets see if I do better on this than the maths logic ones.

I think the statement which applies to the known facts is:-

(c) Some collywobbles have six legs.
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 18:02
I told you easy peasy. Correct

Meg is younger than Beth.
Amy is older than Meg.
Jo is older than Amy.

Therefore (choose one):
(a) Amy is older than Beth.
(b) Beth is older than Amy.
(c) Meg is older than Jo.
(d) Jo is older than Meg.
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raymyjamie
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Re: Mensa Mind teaser

on Sat Jan 06 2018, 18:53
I think the one positive statement is:-

(d) Jo is older than Meg.
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