[Archive!] Pure mathematics, physics, chemistry, etc.: brain-training problems not related to trade in any way - page 505

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MetaDriver:

the result of division necessarily equals 3.

+.

The lowest number starts with either 1 or 21

MetaDriver:

but it's a joke. :)

Well, then it can't at all. Why don't we go over it out loud?

You can't multiply by 2 stopoffs because the result is a maximum of 2 odd digits, and you need 3. And 2*4 = 8.

Ha, you can't do 3 because 3*6 = 8, it doesn't add up to 1...6 in any way.

You can't do 4 because 2*4 is 8, 6*4 = 24, there's no way to get 1 from 8.

That leaves 5.

 

6+5+4+3+2+1=21

so both numbers are divided by 3 (but not divided by nine). the three when divided will be reduced.

 

So,

12****

х

5

---------

6****5

 

A five, when multiplied by any number, yields a result ending in 0 or 5. zero is not the way to go. that leaves us with five.

that's just thinking out loud.

На 2 стопудофф нельзя умножать, т.к. в результате получается максимум 2 нечетные цифры, а надо 3. Ну и 2*4 = 8

You can't multiply by 4, because 2*4 gives 8, 6*4 = 24, there's no way to get 1 from 8.

I can't understand the logic. Can you explain it to me?
 

For the warm-up:

Имеем рычажные весы, 9 кило гречки и две гирьки : 50 гр. и 300 гр.

Нужно за 3 взвешивания отмерить ровно 2 кило.

Go ahead.
 
Well each digit has to be multiplied by a multiplier, so an 8 will pop up somewhere, but to turn it into a 1 you need at least the product of 30 lower digits.
 
TheXpert:
Well each digit has to be multiplied by a multiplier, so an 8 will pop up somewhere, but to turn it into a 1 you need at least the product of 30 lower digits.
That cleared it up a bit, but not completely. Now.
 
MetaDriver:

For the warm-up:

In 2!
 
MetaDriver:

For the warm-up:

Имеем рычажные весы, 9 кило гречки и две гирьки : одна 50гр., вторая 300гр.

Нужно за 3 взвешивания отмерить ровно 2 кило.

Let's go.

we weigh 300

then we put the weight on the buckwheat and deliver 50g. The second weighs 700.

The total is 1,000. Then pile the buckwheat together and add 1000g to the second one. total of 2kg and 3 weighings

how theExpert got 2 weighings I have no idea...

 
sergeev:

weigh 300

then move the weight to the buckwheat and deliver 50g. on the second one, 700.

300+300+50 = 700?
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