The Cost of Household Hardware

A man went to the hardware store to buy items for his house.

1 would cost $.25
12 would cost $.50
122 would cost $.75

When he left the store he had spent $.75, what did he buy?

House numbers.

Posted in Riddles

ABCDE and What?

What comes next in this series?

A B C D E

Hint: It’s not F.

K. The letters represent vitamins, and there is currently no Vitamin F, G, H, I or J.

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Wily Winifred and the Case of the Odd Numbers

Mrs. Shine was having a rough day and wanted a break. So she asked her class to calculate the sum of the first 50 odd numbers. In a few moments, Winifred was at her desk with the correct answer of 2,500. Stunned, Mrs. Shine figured she must have gotten lucky, and sent precocious Winifred back to her seat with the task of finding the sum of the first 75 odd numbers. Again, Winifred returned in seconds with the correct answer (5,625).

How did Winifred find the answer so quickly?

Winifred, being the precocious child she is, realized there was a pattern when computing smaller sums of odd numbers.

First 3: 1 + 3 + 5 = 9
First 4: 1 + 3 + 5 + 7 = 16
First 5: 1 + 3 + 5 + 7 + 9 = 25

Do you see the pattern like our dear friend Winnie?

For the first n odd numbers, the sum is equal to n2. Thus the first 50 is 502, or 2,500, and the first 75 is 752, or 5,625.

Posted in Brain Teasers

Five Hundred Begins It

Five hundred begins it, five hundred ends it,
Five in the middle is seen;
First of all figures, the first of all letters,
Take up their stations between.
Join all together, and then you will bring
Before you the name of an eminent king.

DAVID (Roman numerals).

Posted in Riddles

Apples and Lies

During lunch hour a group of boys from Mr. Bryant’s homeroom visited a nearby grocery store. One of the five took an apple.

Jim said, “It was Hank or Tom”.
Hank said, “Neither Eddie nor I did it.”
Tom said, “Both of you are lying.”
Don said, “No, one of them is lying, the other is speaking the truth.”
Eddie said, “No, Don, that is not true.”
When Mr. Bryant was consulted, he said, “Three of these boys are always truthful but two will lie every time.”

Who took the apple?

Tom took the apple
Jim was telling the truth
Hank was telling the truth
Tom was lying
Don was lying
Eddie was telling the truth
(three telling the truth and two lying)

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Sleeping Killer

A man gets ready for bed at 9:45 pm. He makes himself a drink, then turns off the TV and the lights. The night was windy and there was a major storm. The next day he discovers he was the cause of seven deaths. How is this possible?

He lived in a lighthouse as lighthouse keeper. He turned off all the lights by accident, so a ship with 7 passengers couldn’t negotiate the rocky shores. One would think the light switches in a lighthouse would be more clearly marked.

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How to Save Gas

If you could chose to increase the average fuel economy of a car, which of these would save the most fuel?

1. 10mpg -> 12mpg
2. 12mpg -> 15mpg
3. 15mpg -> 20mpg
4. 20mpg -> 30mpg
5. 30mpg -> 60mpg

It turns out they all save the same amount of fuel.

If you travel 100 miles:

100 / 10 = 10 gallons used
100 / 12 = 8 1/3 gallons used

10 – 8 1/3 = 1 2/3 gallons saved

100 / 30 = 3 1/3 gallons used
100 / 60 = 1 2/3 gallons used

3 1/3 – 1 2/3 = 1 2/3 gallons saved

Posted in Brain Teasers

Kevlar, Fire Escapes and Wipers, Oh My!

What do computer compilers, kevlar, fire escapes and windshield wipers all have in common?

They were all invented by women.

A variation of this brain teaser includes laser printers (they were invented by Gary Starkweather) and bulletproof vests (invented by Casimir Zeglen using silk, though modern vests use Kevlar, so it’s halfway right).

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Broken Before Use

I am broken before you use me,
I brighten your day until I die.

What am I?

Glow sticks that you have to break to start glowing, then they fade out (die).

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Go Back!

Go back. You must strive to find a way to stay alive. What is 4+uo.5?

South. If you read the letters from back to front they make 5.ou+4, or south.

Posted in Brain Teasers