Here’s A Practical Puzzle: How Quickly Can You Toast And Butter Bread?

This week ’s puzzle is an optimisation job : Can you determine the fastest room to goner and butter three gash of bread ? ( It ’s harder than it sounds . )

SUNDAY PUZZLE #35: Optimizing Toast

This week ’s puzzle was suggest by reader Caroline S. Upon further investigation , I found that it retrace back , as many puzzles do , to beat guru Martin Gardner . It ’s a serious one — we hope you enjoy it .

Even the simplest of household undertaking can salute complicated problems in operational inquiry . Consider the formulation of three slices of hot buttered toast . The toaster is the old - fashioned case , with hinged doors on its two sides . It holds two pieces of bread at once but toast each of them on one side only . To toast both sides it is necessary to reach the threshold and overturn the slices .

It takes three seconds to put a slice of simoleons into the toaster , three seconds to take it out , and three seconds to reverse a slice without take away it . Both hands are command for each of these operations , which means that it is not potential to put in , take out , or turn two cut at the same time . Nor is it possible to butter a piece while another fade is being put into the toaster , plough , or taken out . The drink time for one side of a bit of bread is thirty seconds . It takes twelve moment to butter a piece .

Each piece is butter on one side only . No side may be butter until it has been pledge . A cut toast and buttered on one side may be return to the wassailer for toasting on its other side . The toaster is warm up at the start . In how short a prison term can three slices of lucre be toast on both sides and buttered ?

We ’ll be back next hebdomad with the resolution — and a new teaser ! get a great brainteaser , original or otherwise , that you ’d like to see featured?E - mail me with your recommendations.(Be sure to include “ Sunday Puzzle ” in the subject line . )

SOLUTION To Sunday Puzzle #34: Complete The Series

Last calendar week , I deliver you with a visual riddlethe solution to which , I asserted , was not “ 6 . ”

https://gizmodo.com/the-answer-to-this-riddle-is-not-6-1709650686

As it wrench out , this brain-teaser has many correct solutions . As commenter Platypus Man put it : “ There ’s so lilliputian information [ present ] , it could be just about anything if you properly rationalize it . ”

By that dead sound logic , the answer could be , as Platypus Man proposes , five :

Put a horizontal line in the middle and you have three fractions . 1/2 to 3/4 is an addition of 1/4 , so the last reply is 1 . Given we already have the 5 , the bottom number must be 5 as well .

It may not be the intended answer , but I do n’t see how it ’s any less valid .

It could be , as commenter wigglecandy writes , 6.8 :

The first row is inputs for a routine f(n ) . In this font f(n ) is the norm of the first n matching primes minus one .

f(1 ) = 3 – 1 = 2

f(3 ) = ( 3 + 5 + 7)/3 – 1 = 4

f(5 ) = ( 3 + 5 + 7 + 11 + 13)/5 – 1 = 6.8

It could even be , as lector K. Praznik offer by e - mail , 10 :

( 1 * 3 ) + ( 3 - 1 ) = 5 // ( 1 * 3 ) – ( 1 - 3 ) = 5

( 2 * 4 ) + ( 4 - 2 ) = 10 // ( 2 * 4 ) – ( 2 - 4 ) = 10

So my answer to the sunday puzzle # 34 is 10 .

These solution are all correct , but none of them is the answer I was look for . The solvent I was looking for was “ R. ”

“ R ” as in “ reverse . ”

That is , the convention in which the numbers come along in the puzzle is the same as one commonly plant on the gear levers of cars with five - focal ratio manual transmittance :

Pixwatch2

That the solution was a letter and not a routine was what I thought made this riddle “ shifty . ” As it turns out , several of you hadother , more colorfulways of line it , which was fair ; after all , it ’s not like there ’s a universally accepted gearstick layout ( for five - velocity transmittance or otherwise ):

You get the flick . The riddle was too open - over . Whether you interpreted it as a mathematical puzzle , or an automotive design puzzle , it was ill posed , and that ’s on me . Puzzle - posing is an art in and of itself , and it ’s easy to mess up . For a resolution to be satisfying , the person dumbfound the teaser needs to provide enough information that the puzzler is unambiguously solvable , but not so much that it yield too much aside .

In the case of last hebdomad ’s puzzle , there are at least a match ways I could have posed it more in effect . Mostly , I could have provided decipherable hints . One clue I did allow for was , in retrospect , too subtle : Nowhere in last workweek ’s puzzle did I enquire what number should take the blank space of the dubiousness mark . But the good proffer I insure on how to elucidate the enigma come from commenterneuroguy . It “ might aid , ” they write , “ to tally some contrast ” :

Dji Drone