OT: Mathematical Conundrum II

[Jim_S]

Stupid boy :-)

[News]

I first read that in a book belonging to my Father, at least 50 years ago. I can still 'see' the book - Riddles in Mathematics. Back then, the question was in shillings, not pounds. Took me a *long* time to work it out :-)

[Albert Zweistein]

This one:-

hardcover £4, kindle edition £10.27 Now that is a conundrum. :)

[Cursitor Doom]

Where did you get 5d from?

[polygonum]

Change when using a tanner to buy four farthing chews? :-)

[dennis]

Half of 10 pence. You do know what pence are? There were 240 of them to a pound, 12 to a shilling. £sd.

[polygonum]

And the pennies we have today are NOT abbreviated to "d".

[pamela]

Did you use to read Martin Garner's puzzles in Scientific American?

I remember reading his column about non-periodic tiling. Maybe I should have asked our tiler for a non-periodic design when he was tiling our new bathroom. :-)

[Bob Eager]

It's one answer.

But pence are new money too, so the answer can also be 105 pence and 5 pence.

[Bob Eager]

And there are 100 pence to the pund these days.

[News]

Well done that man! Actually, my Father's edition was paperback, and I can see it as blue. Exactly like this, in fact :

A bargain at £2.99 :-)

[News]

Sadly not. Maths was never my strong suite. Even today, I prefer crosswords and have never been attracted to Sudoku.

But would non periodic tiling create less dust? :-)

[Jonno]

News scribbled

This still doing the rounds?

Classic redirection. £2 is part of charge, £1 x3 is the change.

[Brian-Gaff]

Sorry sir, we don't sell them separately. Brian

[Brian-Gaff]

But who uses shillings any more? I particularly do not like non real world questions. You could invent a currency based on lumps of coal for that mater. Brian

[Tim+]

Horses are still sold in guineas (21 shillings) are they not?

Tim

[PeterC]

The quickest way is to look and see 42 - although I can often do that sort of thing, I sometimes take an age to check it as the answer seems to obscure the method and, like Albert, then need the iterative process and forget where I've got to. Sometimes I give a very rapid answer, others are impressed, I'm then not sure so, as mentioned earlier, keep a straight face and hope!

[PeterC]

Or, as in Morrisons, brush 99p and handle 99p - how much for the two? At the till: 99p. I queried it and it was correct. Seems that the answer isn't arithmetical after all.

[Tim+]

Sometimes thinking gets in the way of getting the right answer. When I'm doing the Saturday Times killer Sudoku I often have to add together lots of numbers. If I do it fast the answers often just pop into my head. If I slow down and think about it, I have to slow down a lot to achieve the same accuracy.

Tim

[NY]

True, except that the guinea is specified as £1.05 rather than 21 shillings these days.