(October 22, 2017 at 5:39 pm)BrianSoddingBoru4 Wrote: I came across one that may prove a right old poser:

It is a commonly accepted, but erroneous, belief that 7 x 13 = 91.  In fact, 7 x 13 = 28.  The can be checked by demonstrating that 28 / 7 = 13, and by showing that 13+13+13+13+13+13+13 = 28.

Hint:  Colgate Toothpaste

After a reasonable time for those who wish to have a go have had one, I'll post the solution.


Boru

(October 17, 2017 at 10:33 am)pocaracas Wrote: How about we go for a classic mathy type riddle?

Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 3, and the host, who knows what is behind the doors, opens another door, say No. 1, which has a goat. He then says to you, "Do you want to pick door No. 2?"

Is it to your advantage to switch your choice?

(October 11, 2017 at 4:05 pm)Losty Wrote: Let's post some fun mathish riddles. I'll start

In a lake, there is a patch of lily pads. Every day, the patch doubles in size. If it takes 48 days for the patch to cover the entire lake, how long would it take for the patch to cover half of the lake?

Put your answers in hide tags so you don't ruin it for someone else

(October 11, 2017 at 4:24 pm)mlmooney89 Wrote: A white house is made out of white bricks. A blue house is made out of blue bricks. A yellow house is made out of yellow bricks. A red house is made out of red bricks. What is a green house made of?

Quote:A plane is flying from New York to Ontario. It ends up crashing on the border of the US and Canada. I mean smack dab in the middle of the border, no more in America than it is in Canada. Knowing this which country do you bury the survivors in?

(October 18, 2017 at 11:08 am)Whateverist Wrote: Which reminds me ..

What is the rule by which the following numbers return these scores?



13 = 0
10 = 1
28 = 2
1928 = 3

(November 14, 2017 at 5:00 pm)Grandizer Wrote:

(October 18, 2017 at 11:08 am)Whateverist Wrote: Which reminds me ..

What is the rule by which the following numbers return these scores?



13 = 0
10 = 1
28 = 2
1928 = 3

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13 is prime, so not divisible by 2, so 0
10 / 2 = 5, 1 step, so 1
28 / 2 = 14, 14 / 2 = 7, 2 steps, so 2
1928 /2 = 964, 964 / 2 = 482, 482 / 2 = 241, 3 steps, so 3

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(October 22, 2017 at 5:39 pm)BrianSoddingBoru4 Wrote: I came across one that may prove a right old poser:

It is a commonly accepted, but erroneous, belief that 7 x 13 = 91.  In fact, 7 x 13 = 28.  The can be checked by demonstrating that 28 / 7 = 13, and by showing that 13+13+13+13+13+13+13 = 28.

Hint:  Colgate Toothpaste

After a reasonable time for those who wish to have a go have had one, I'll post the solution.


Boru

(November 14, 2017 at 5:26 pm)Whateverist Wrote:

(November 14, 2017 at 5:00 pm)Grandizer Wrote:

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13 is prime, so not divisible by 2, so 0
10 / 2 = 5, 1 step, so 1
28 / 2 = 14, 14 / 2 = 7, 2 steps, so 2
1928 /2 = 964, 964 / 2 = 482, 482 / 2 = 241, 3 steps, so 3

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Oh man are you ever going to hate the solution to this one.  So not-mathy.

Prepare to puke:

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The number refers to the number of closed figures formed in the numerals used to write the numbers and not the numbers themselves.  
13 = no closed figures
10 = 1 closed figure in the zero
28 = 2 closed figures, both in the eight
1928 = 3 one in the nine and two more in the eight for three total

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Quote:You sure you're not mistaking the number 13 for the number 4?

(November 14, 2017 at 6:26 pm)Haipule Wrote:

(October 22, 2017 at 5:39 pm)BrianSoddingBoru4 Wrote: I came across one that may prove a right old poser:

It is a commonly accepted, but erroneous, belief that 7 x 13 = 91.  In fact, 7 x 13 = 28.  The can be checked by demonstrating that 28 / 7 = 13, and by showing that 13+13+13+13+13+13+13 = 28.

Hint:  Colgate Toothpaste

After a reasonable time for those who wish to have a go have had one, I'll post the solution.


Boru

In vortex math there is no zero and no number higher than 9. Therefore, since 13 is higher than 9, it is reduced to 1 + 3 = 4. Therefore, 7 x 4 = 28 However, 28 is higher than 9 and is reduced to 2 + 8 = 10 which is also higher than 9 and reduced to 1 + 0 = 1. Conclusion: 7 x 13 = 1 or, shortcut 7 x 13 = 91 where 9 + 1 = 10 reduced to 1 + 0 = 1

(November 14, 2017 at 6:26 pm)Haipule Wrote:

(October 22, 2017 at 5:39 pm)BrianSoddingBoru4 Wrote: I came across one that may prove a right old poser:

It is a commonly accepted, but erroneous, belief that 7 x 13 = 91.  In fact, 7 x 13 = 28.  The can be checked by demonstrating that 28 / 7 = 13, and by showing that 13+13+13+13+13+13+13 = 28.

Hint:  Colgate Toothpaste

After a reasonable time for those who wish to have a go have had one, I'll post the solution.


Boru

In vortex math there is no zero and no number higher than 9. Therefore, since 13 is higher than 9, it is reduced to 1 + 3 = 4. Therefore, 7 x 4 = 28 However, 28 is higher than 9 and is reduced to 2 + 8 = 10 which is also higher than 9 and reduced to 1 + 0 = 1. Conclusion: 7 x 13 = 1 or, shortcut 7 x 13 = 91 where 9 + 1 = 10 reduced to 1 + 0 = 1

(November 15, 2017 at 11:58 am)Fireball Wrote:

(November 14, 2017 at 6:26 pm)Haipule Wrote: In vortex math there is no zero and no number higher than 9. Therefore, since 13 is higher than 9, it is reduced to 1 + 3 = 4. Therefore, 7 x 4 = 28 However, 28 is higher than 9 and is reduced to 2 + 8 = 10 which is also higher than 9 and reduced to 1 + 0 = 1. Conclusion: 7 x 13 = 1 or, shortcut 7 x 13 = 91 where 9 + 1 = 10 reduced to 1 + 0 = 1

Vortex math? That's the bastard spawn of the Time Cube and a jellyfish.