A Fistful of Brain Teasers
Posted by: Don Atkinson on 13 November 2017
A Fistful of Brain Teasers
For those who are either non-British, or under the age of 65………. The UK used to have a brilliant system of currency referred to as “Pounds, Shillings and Pence”. Simplified to £ ״ s ״ d. No! Don’t ask me why the “Pence” symbol is a “d”, just learn it and remember it !
A £ comprised 20 Shillings and a Shilling comprised 12 Pence. Thus a £ comprised 240 Pence. I reckon that both Microsoft and Apple would have difficulty with these numbers in their spreadsheets, more so if we included Guineas, Crowns, Half-Crowns and Florins. However, I digress..............
The purpose of the explanation is to assist with the first two or three teasers that follow. So just to ensure a reasonable comprehension has been grasped…. ….. if each of three children has £3 − 7s − 9d, then collectively they have £10 − 3s − 3d Got the idea ? Good ! Just try 5 children, two each with £4 − 15s − 8d and three each with £3 − 3s − 4d. How much do they have between them ? (this isn’t the first brain teaser, just the basic introduction with some “homework”, the Teasers follow)
Now this one should be straightforward and easy…………!
Bruce's Bashers
In the Yorkshire Dales inter-village cricket Cup Final, Arthur’s Eleven batted first and were over the moon with their run score.
Bruce’s Bashers responded with a somewhat mediocre three-quarters of Arthur’s Eleven score.
In their second innings, Arthur’s Eleven, only managed three quarters of Bruce’s Bashers first innings score, and Bruce’s Bashers responded with a disappointing three quarters of those runs in their second innings !
So the run score for each innings was three quarters of the previous innings.
Arthur’s Eleven were nevertheless delighted to have won by 50 runs.
How many runs did each team score in each innings ?
Don Atkinson posted:Now this one should be straightforward and easy…………!
Bruce's Bashers
In the Yorkshire Dales inter-village cricket Cup Final, Arthur’s Eleven batted first and were over the moon with their run score.
Bruce’s Bashers responded with a somewhat mediocre three-quarters of Arthur’s Eleven score.
In their second innings, Arthur’s Eleven, only managed three quarters of Bruce’s Bashers first innings score, and Bruce’s Bashers responded with a disappointing three quarters of those runs in their second innings !
So the run score for each innings was three quarters of the previous innings.
Arthur’s Eleven were nevertheless delighted to have won by 50 runs.
How many runs did each team score in each innings ?
128, 96, 72, 54
Nicely scored Eoin !
Cycle Journey ! (but of course it could be a car, or a motor bike, or simply a walk.......)
Two cyclists, on the road at Aldermaston wish to go to Burfield which for the sake of brevity are marked as A and B on the map above.
Boris the Biker decided to go via the crossroad at Downton (D) which is 6 miles, then take the straight road to Burfield which is another 15 miles.
(All roads are dead straight and the junction at Downton is a 90 deg crossroad)
Charlie the Challenger said he would take the upper road via Compton (C)
Strangely enough, they found the distance each way to be exactly the same.
Can you answer the simple question……” How far is it from Aldermaston to Compton ?”
Picked this up on holiday, and seemed easy enough to not take any time, and indeed it was: 3 1/3rd miles.
pythagorus
bc^2=(ac+6)^2+15^2
Ac+bc=21
Ac=21-bc
Bc^2=(27-bc)^2+225
Bc^2= bc^2-54bc+729+225
954-54bc=0
954=54bc
Bc=17.667
Ac=21-17.667=3.333
Innocent Bystander posted:Picked this up on holiday, and seemed easy enough to not take any time, and indeed it was: 3 1/3rd miles.
pythagorus
bc^2=(ac+6)^2+15^2
Ac+bc=21
Ac=21-bc
Bc^2=(27-bc)^2+225
Bc^2= bc^2-54bc+729+225
954-54bc=0
954=54bc
Bc=17.667
Ac=21-17.667=3.333
yep ! I noticed that I posted a couple of "moderate" ones and nobody seemed willing to tackle them, so I searched high and low for a couple of "easy" ones. Well spotted
......and nice explanation of your solution.
Another Easy one......
Talking to two of my students the other day, I asked them to state their ages. They did so.
Then to test their arithmetical powers I asked them to add the two ages together.
One gave me 44 as his answer and the other gave me 1280.
I immediately realised that the first had actually subtracted their ages, whilst the other had multiplied them together.
What are their ages ?
Don Atkinson posted:Another Easy one......
Talking to two of my students the other day, I asked them to state their ages. They did so.
Then to test their arithmetical powers I asked them to add the two ages together.
One gave me 44 as his answer and the other gave me 1280.
I immediately realised that the first had actually subtracted their ages, whilst the other had multiplied them together.
What are their ages ?
Never mind that, when do their lessons in English comprehension start?!
The ages should be 64 and 20, but Christopher has made a very valid point
Don Atkinson posted:Another Easy one......
Talking to two of my students the other day, I asked them to state their ages. They did so.
Then to test their arithmetical powers I asked them to add the two ages together.
One gave me 44 as his answer and the other gave me 1280.
I immediately realised that the first had actually subtracted their ages, whilst the other had multiplied them together.
What are their ages ?
64 and 20, by trying a couple of pairs of factors of 1280. Formal method would be have x-y=44, x*y=1280, get the quadratic and solve.
Christopher_M posted:Don Atkinson posted:Another Easy one......
Talking to two of my students the other day, I asked them to state their ages. They did so.
Then to test their arithmetical powers I asked them to add the two ages together.
One gave me 44 as his answer and the other gave me 1280.
I immediately realised that the first had actually subtracted their ages, whilst the other had multiplied them together.
What are their ages ?
Never mind that, when do their lessons in English comprehension start?!
If the question was “what is the sum of your ages”, I could understand, if neither’s education had included the verb to sum.
Mind you, with those ages, one probably has had no contact with maths since leaving school best part of 50 years ago, and the other probably dossed through it ... and both must have been desperate otherwise they wouldn’t have chosen Don as a teacher!
Innocent Bystander posted:Christopher_M posted:Don Atkinson posted:
If the question was “what is the sum of your ages”, I could understand, if neither’s education had included the verb to sum.
My inner pedant forces me to point out that “sum” in the question is using the word as a noun.
Chris has a valid point
Mulberry has the right answer
Eoin also has the right answer and a neat outline of the “formal” methodology
IB raises an interesting aside. Fortunately I didn’t use the word “sum”........whether it’s a noun or a verb
makes me realise just how carefully I need to be when drafting these teasers ........i’ll recheck my next one very, very carefully - I might be some time.....
Eoink posted:Innocent Bystander posted:Christopher_M posted:Don Atkinson posted:
If the question was “what is the sum of your ages”, I could understand, if neither’s education had included the verb to sum.
My inner pedant forces me to point out that “sum” in the question is using the word as a noun.
Touché!
Well, after the little diversion over the word "sum". I thought "words" and "riddles" might be more up your street.
He went to the wood and caught it
He sat himself down and sought it
Because he could not find it
Home with him he brought it
What was it ?
Of course, it could be a number of things I guess, but the thing about riddles is that only my answer is correct no matter how reasonable, logical or obvious all the other answers might be
A flea or tick?
Eoink posted:A flea or tick?
Not sure that fleas and ticks are particularly associated with wood or woods.
Not that I’m any further! Many things you could catch in a wood, but why sit down to seek it? And the implications are both that it was difficult to find (so, likely quite small) and that he would not have brought it home if he had found it when he sought it (maybe undesirable, or just better left in the wood). From the latter two points I get the flea/tick idea, but I don’t feel that fits the whole.
I struggled with the first 2 lines, tick was my attempt to think of something you might get in the woods. (I spend most of my life in a city.) I rejected teddy bears' picnic for not fitting the other 3 lines. Sitting down to find something felt like something in your shoe, but that got me no further really.
Well, the concept of ticks is reasonable. But as I said in the post, reasonable per se, isn’t good enough ! Nice try !
bear in mind that most of us don’t know we’ve picked up a tick, so wouldn’t be seeking it whilst still in the woods.
But your connection with “wood” and “felt like something in my.....” are worth developing.
Is it a splinter in a toe? So the wood is a piece of wood which you catch with a bare foot, get a splinter in a toe, sit down to try to remove it, then come home still with the splinter under your skin.
Eoink posted:Is it a splinter in a toe? So the wood is a piece of wood which you catch with a bare foot, get a splinter in a toe, sit down to try to remove it, then come home still with the splinter under your skin.
Sounds good!
I
Eoink posted:Is it a splinter in a toe? So the wood is a piece of wood which you catch with a bare foot, get a splinter in a toe, sit down to try to remove it, then come home still with the splinter under your skin.
I think that will do nicely.................although the official object is a "thorn"
It just goes to show how irritating these Riddles can be !
Here's another to fascinate or irritate.........
Before my birth I had a name,
But soon as born I chang'd the same;
And when i'm laid within the tomb,
I shall my father's name assume.
I change my name three days together,
Yet live but one, in any weather.
Don Atkinson posted:I
Eoink posted:Is it a splinter in a toe? So the wood is a piece of wood which you catch with a bare foot, get a splinter in a toe, sit down to try to remove it, then come home still with the splinter under your skin.
I think that will do nicely.................although the official object is a "thorn"
It just goes to show how irritating these Riddles can be !
My challenge, if challenges were allowed, is that you don’ catch a thorn (or splinter), rather it catches you...
Don Atkinson posted:Here's another to fascinate or irritate.........
Before my birth I had a name,
But soon as born I chang'd the same;
And when i'm laid within the tomb,
I shall my father's name assume.
I change my name three days together,
Yet live but one, in any weather.
That’s one I’ve heard before and remember (or at least I think I do, though I don’t recall how weather fits) - so I’ll keep out of it for now