Alter By a Single Stroke

How can you alter the following equation by a single stroke to make it correct?

5 + 5 + 5 = 550

5 4 5 + 5 = 550

Add a diagonal line on the top left of the first plus sign to convert + into a 4. You could also put a slash through the equal sign to make ≠ (not equal) but that’s not as cool.

Posted in Brain Teasers

Three Cuts to Turn a Round Cake Into Eight Equal Slices

How can you cut a round cake three times to make eight equal slices?

Cut #1 – Down the center of the cake (vertically) leaving two equal halves.
Cut #2 – Across the center of the cake (horizontally) leaving four equal slices.
Cut #3 – Through the middle edge of the cake slicing all four of the pieces in equal halves, leaving eight equal slices (four equal tops and four equal bottoms).

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Run Smoother Than Any Rhyme

What runs smoother than any rhyme, loves to fall but cannot climb?

Water

Posted in Riddles

Aiden and Sofia Buying Candy

Aiden and Sofia were debating a major purchase of candy. They calculated that they could get three bags of jelly beans and two bags of chocolate for 24 cents, which was just under their limit of 25 cents. They found they could also get four bags of chocolate and two bags of jelly beans for the same 24 cents. How much did each bag of candy cost?

Jelly beans are 6 cents and chocolate is 3 cents.

Posted in Brain Teasers

Three Two Three Sequence

What number belongs at the beginning of this sequence?

?, 3, 2, 3, 9, 2, 4, 8, 4, 3, 7, 6

3 ½.

If you break up the numbers into groups of 4, a,b,c,d, then 2 × |a – d| = |b – c|.

9 2 4 8 → 2 × |9 – 8| = |2 – 4|, or 2 × 1 = 2
4 3 7 6 → 2 × |4 – 6| = |3 – 7|, or 2 × 2 = 4, so
n 3 2 3 → 2 × |3 ½ – 3| = |3 – 2|, or 2 × ½ = 1;

I’m not sure this is the correct solution, but it’s the best I’ve found so far. Email me if you know of a better one.

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Which Are True and Which Are False?

A. When a car is driven forwards the wheels rotate counter-clockwise.
B. If a clock is put forward 1 1/4 hours the minute hand moves through 450°
C. When a clock reads 4.10 the acute angle between the hands is exactly 60°

A. False – The near-side wheels rotate counter-clockwise, but the far-side wheels rotate clockwise.
B. True
C. False – The acute angle is a little more than 60° because by the time the minute hand reaches 10, the hour hand will have moved slightly past the 4.

Posted in Brain Teasers

Fill in the Missing Element

Here is a series of numbers:

16 06 68 88 ___ 98

What belongs in the blank spot?

87 is the common answer to this, but it has to be flipped upside down, so I consider L8 more correct.

If you flip the numbers horizontally by 180 degrees:

86 87 88 89 90 91

You see that the blank spot is 87, counting from 86 to 91. However, you need to flip it around, so it becomes L8.

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Dancing All The Time

Moving to and fro,
Dancing all the time.
Only to be moved by others
To allow them to pass by.

What am I?

A door.

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Job Hopping Jeremy

Jeremy was making $10 an hour at his summer job, but he hated the work. He decided to take a 50% pay cut to work at an easier job. He liked his new job at first, then grew bored and found another job paying 50% more than he was currently making. What was his hourly pay at the third job?

$7.50. If you guessed $10, don’t feel bad. Percentages can be counter intuitive.

First job: $10/hour
Second job: $10/hour – ($10 &times .5) = $5/hour
Third job: $5/hour + ($5 × .5) = $7.50

Posted in Brain Teasers

A Family of Seven

I’m a family of seven,
Two are bitter and harsh,
Four are twins,
The last is the warmest of all.

What family am I?

The Seven Seas. The first two are bitter and harsh, the north and south ones are the twins, and the Indian Ocean is the warmest of the bunch.

  1. Arctic Ocean
  2. Antarctic Ocean
  3. North Atlantic Ocean
  4. South Atlantic Ocean
  5. North Pacific Ocean
  6. South Pacific Ocean
  7. Indian Ocean
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