A Seemingly Simple Math Problem

What is the answer to this problem?

1 + 1 + 1 + 1 + 1
1 + 1 + 1 + 1 + 1
1 + 1 × 0 + 1 = ?

30.

There are two tricks to this one. The first is 1 × 0. But it’s mostly there as a distraction. Yes, 1 × 0 is 0, but that doesn’t affect anything else in the equation. The second, far trickier element is that the lines ending with 1 don’t have a + sign next to them. That means they should be combined with the following line.

Let’s put the equation all on one line, shall we?

1 + 1 + 1 + 1 + 11 + 1 + 1 + 1 + 11 + 1 × 0 + 1 = ?

And the answer to that equation is 30.

Posted in Brain Teasers

Dark As Midnight

What is dark as midnight but is still night?
The word has 7 letters, starts with a B and ends with an E.

Bedtime

Posted in Riddles

Planting Trees on Arbor Day

On Arbor Day the fourth grade class began planting trees. They finished planting five trees before the fifth grade class arrived. But they accidentally planted them on the fifth grade side of the street.

The fourth-graders crossed the street to start over, and the fifth-graders planted the remaining trees. They finished first and felt bad for the fourth-graders, so they crossed the street and planted five trees. They planted another five trees at which point all of the trees had been planted.

By how many trees were the fifth-graders ahead of the fourth-graders?

Ten. The fifth-graders planted five more trees than they were assigned, and the fourth-graders planted five fewer than their assignment.

Posted in Brain Teasers

Reverse to Equal Ten

Which two of these rows can be reversed so the total of each row, across and down, equals 10?

A. 5 4 1
B. 6 1 3
C. 3 5 2

Rows B and C, becoming:

A. 5 4 1
B. 3 1 6
C. 2 5 3

Posted in Brain Teasers

Decorating With Tiles

You are decorating for spring and you’ve found a bargain. A huge box of beautifully decorated tiles, enough to provide a border in two rooms. You really can’t figure out how to arrange them. If you set a border of two tiles all around, there’s one left over. If you set three tiles all around or four or five or six there’s still one tile left over. Finally you try a block of seven tiles for each corner and you come out even. What is the smallest number of tiles you could have to get this result?

301. This is the smallest number that even divides by 7, but when divided by 2, 3, 4, 5, and 6 gives you one left over.

Posted in Brain Teasers

Built From Anything You Don’t Like

I’m built from anything you don’t like,
You’re using me right now in fact,
I am one but represent many,
When attacked I’m easily cracked,
I’m created in seconds but live forever
And though you may not understand,
I’ll help you do well but be careful my friend,
Hurt me and you won’t withstand.

What am I?

Character (or characters).

Kids are often told, when dealing with unpleasant things, that it builds character. You’re reading the characters this riddle is written with. In computer science a char is often represented by one byte and can store any character you want.

When politicians have their character besmirched it can swiftly change the voting public’s mind about them. Characters in novels are created with a few lines but live on in our memories. And if your character or reputation is damaged, you may find it hard to deal with the aftermath.

And here’s a great quote from Warren Buffet on your character.

“It takes 20 years to build a reputation and five minutes to ruin it. If you think about that, you’ll do things differently.” — Warren Buffet

Posted in Riddles

Ten Times Two is 0218

10 × 2 = 0218
20 × 2 = 1421
30 × 2 = 1632
40 × 2 = ?

2840.

This makes the first column the start of the Fibonacci series: 0, 1, 1, 2.
The second column is the even numbers: 2, 4, 6, 8
The third column is counting up by ones: 1, 2, 3, 4
And the last column is the answer in the first row in reverse: 8, 1, 2, 0.

Don’t ask what 50 × 2 equals. I have no idea. :)

Thanks to Jim for helping with the solution.

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Remote Cooking

You are a cook in a remote area with no clocks or other way of keeping time other than a four-minute and a seven-minute hourglass. On the stove is a pot of boiling water. Jill asks you to cook a nine-minute egg in exactly 9 minutes, and you know she is a perfectionist and can tell if you under cook or overcook the egg by even a few seconds. How can you cook the egg for exactly 9 minutes?

1. Flip both hourglasses over and drop the egg into the water.
2. When the 4-minute timer runs out, flip it over (4 minutes elapsed, 3 remaining on the 7-minute timer).
3. When the 7-minute timer runs out, flip it over. (7 minutes elapsed, 1 remaining in the 4-minute timer)
4. When the 4-minute timer runs out, flip the 7-minute timer over. (8 minutes elapsed. 6 minutes remained in the 7-minute timer, but flipping it over leaves one minute’s worth of sand on top. When it runs out exactly nine minutes will have elapsed.)

Posted in Brain Teasers

Apples Rebus

What does this represent?

APPLE
APPLE
APPLE
aPPLe
APPLE

I haven’t figured this out yet. Bad apple doesn’t really fit with the lowercase letters. They’re both vowels, but I don’t know if that’s relevant. The fourth one looks kind of like a hill, could it be apple hill?

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Weighty Wine

How much does a bottle of wine weigh if it is 1 kilogram plus half its own weight?

2 kg.

If we let half of the bottle’s weight be “n”, then we get the following equation: n/2 + 1kg = n (the bottle’s weight).

Solve for n:
n/2 + 1 = n
1 = n/2
2 = n

Posted in Brain Teasers