OT: Mathematical Conundrum II

A bat and a ball together cost 1 pound ten pence and the bat costs one pound more than the ball. How much is the ball?

Reply to
Cursitor Doom
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One shilling!

Avpx

Reply to
The Nomad

5p Why do you ask?
Reply to
Jim_S

Not available separately. Ye have to buy both, and put the bat up on eBay to get ya money back...

Reply to
Adrian Caspersz

Sorry to deviate, but on Friday I was working for a regular customer who is a retired maths teacher. He likes to watch and ask questions.

One job was to cut off a thin wall metal tube at ground level (clothes dryer thingy),

Out came the trusty angle grinder, lots of sparks, job done. He was gobsmacked, obviously never seen one before.

He asked how fast the disc was spinning and what diameter it was, thought for about 30 seconds and said "The edge speed of the disc is around 150 mph!

No calculator or bit of paper, he did it in his head!

Reply to
David Lang

David Lang wrote in news:3lj6y.145177 $ snipped-for-privacy@fx39.am:

Sounds like a proper teacher (as I was). Just say the first thing that comes into your head with a straight face and nobody ever questions it :-)

Reply to
Jim S

Does this mean eBay sellers fees have to be inserted into the original calculation?

Reply to
Albert Zweistein

In message , Cursitor Doom writes

My old and tired brain managed to work that out, but, sadly, I just asked my 14 year old and three of his hoodlum friends, without getting a correct answer :-(

Three out of four could explain stationary/ery.

Reply to
News

I haven't checked to be honest!

Reply to
David Lang

Its the sort of thing I almost know from having calculated too many model aeroplane propellor tip speed formulae.

Reply to
The Natural Philosopher

Of course. The bat and ball sells with a retail mark-up to include such things. We are told how much the pair costs, but are somewhat out to lunch on how much the Bat alone will sell for to recuperate the expenditure.

On eBay, BNIB, 99p No reserve, delivery Xmas day.

Can't fail.

Reply to
Adrian Caspersz

There were _twenty_ shillings to a pound...

Reply to
S Viemeister

Let's say 115mm disc, and 11K RPM, so that is 11000 x 0.115 x pi / 60 = ~66 m/sec, so just under 148 mph

Reply to
John Rumm

Exactly...

the whole shebang is 22 shillings

so if the ball is a shilling the bat is 21 shillings, or a guinea, which is a quid more than the ball the lot added together is 22 shillings

Reply to
The Natural Philosopher

Pfft. Kids today. One shilling (5 "new pence") is perfectly correct.

Tim

Reply to
Tim+

If you must use old money, then no.

Ball is 5d. Bat is £1-0s-5d

Bat + ball = £1-0s-10d

Bat - ball = £1-0s-0d

QED!

Reply to
Chris Hogg

5p.
Reply to
Tim Streater

I think it boils down to two simple simulatious equations if you want to do it properly. But if you can't, then....

The obvious kneejerk answer is 10p. Let's 'plug that figure in' and try it:

That would make the bat alone 1.10 so can't be true since we need to see

1.10 for the pair. Try 9p: Makes the bat 1.09. 109+9p = 1.18 so another overshoot. Try 8p.. and so on til you get a hit.

The 14 yr old thugs would have figured it out the long way eventually, I'm sure.

Reply to
Cursitor Doom

Maybe not one of my apprentices.

Although one apprentice managed to improvise and partially do something correct at an office last week.

The task was "when leaving the building to fetch stuff from the van just use the fire extinguisher to prop the door open as it is a self locking and self closing door"

I saw him try to use the fire extinguisher to prop the door open. Everytime he tried the door started to close as the fire extinguisher was far to close the the door hinges and so it slid along the floor as the door closed.

After several attempts - non of which worked - as they did not involve moving the fire extinguisher more that 6 inches away from the door hinges (do they not teach force x distance at school anymore?) he laid the fire extuingisher on its side and jammed the trigger between the closing door and the door frame.

Reply to
ARW

Give over. It's a lot easier than that. Try:

x + (x + 100) = 110

This gives x = 5

Simples. You can do this in your head in about 2 secs.

Reply to
Tim Streater

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