What Times Seven Is All Fours?

What is the smallest integer that is all 4s when multiplied by 7?

63,492 × 7 = 444,444

Posted in Brain Teasers

Today Before Yesterday

I am a rare case where today comes before yesterday. What am I?

A dictionary

Posted in Riddles

Go in Dry, Come Out Wet

I go in dry and come out wet,
The longer I’m in, the stronger it will get.

What am I?

A tea bag or cement.

Posted in Riddles

I Come in the Form of a Question

I come in the form of a question. If you don’t know the answers, you will think a lot, but when you know or you are being told the answer it sounds simple that you will think everybody can easily know.

A riddle or brain teaser.

Posted in Riddles
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What Digit Does Each Letter Represent?

This is what you know:

1. Each letter represents a different digit from 1 to 9
2. The total of each row is 17.
3. (B × B) + B + F = A
4. C × F = EF (a 2-digit number, not their product)

A B C
D E F

What digit does each letter represent?

A = 7
B = 1
C = 9

D = 8
E = 4
F = 5

A + B + C = 17
D + E + F = 17
B2 + B + F = A
C × F = EF

To begin with, B has to be a 1 or 2 or else A wouldn’t be a single digit. Plug in B = 2, gives you 6 + F = A, meaning F and A can only be (1,7) or (3,9). To get 17, C would have to be 8 or 6, but those values don’t work for C × F = EF. So B must be 1.

2 + F = A means F and A can be (2,4), (3,5), (4,6), (5,7), (6,8) or (7,9). To get 17 on the top row, the only option that leaves C as a single digit is F = 5 and A = 7.

C × F = EF
9 × 5 = 45, so E = 4 and D = 8 to make the second row equal to 17.

Posted in Brain Teasers

What Binds These?

What word binds all of these together?

Burglar
Fat
Copy
Bag
Nap

Cat.

Cat burglar
Fat cat
Copy cat
Let the cat out of the bag
Cat nap

Posted in Riddles

Six Apples

A mother of three children had six apples. She gave two to each and yet 4 remained. How was this possible?

She gave the same 2 apples to each child in succession.

Posted in Brain Teasers

Full of Holes Yet Full of Water

I’m full of holes, yet I’m full of water. What am I?

A sponge.

Posted in Riddles

The Potato Paradox

Fred brings home 100 pounds of potatoes, which (being purely mathematical potatoes) consist of 99 percent water. He then leaves them outside overnight so that they consist of 98 percent water. What is their new weight?

50 pounds.

100 lb of potatoes with 99% water weight means there’s 99 lb of water and 1 lb of solids, a 1:99 ratio.

If the water decreases to 98%, then the solids account for 2% of the weight. The 2:98 ratio reduces to 1:49. Since the solids still weigh 1 lb, the water must weigh 49 lb for a total of 50 lbs for the answer.

Read more at the Potato Paradox wikipedia page.

Posted in Brain Teasers

Number Abbreviations

What do these represent?

24 = HiaD
26 = LotA
7 = DotW
9 = LoaC
12 = SotZ
88 = PK

24 hours in a day
26 letters of the alphabet
7 days of the week
9 lives of a cat
12 signs of the Zodiac
88 piano keys

Posted in Brain Teasers