Brain Teasers Category

Picking Red Balls

A bag contains 64 balls of eight different colors. There are eight of each color (including red).
What is the smallest number you would have to pick, without looking, to be sure of selecting 3 red balls?

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59. The first 56 balls could all be non-red colors. If that happened, you’d have to choose from the 8 remaining balls, all of which would be red.

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Seemingly Simple Math

What is the answer to this math problem:

8 ÷ 2 (2 + 2)

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16 or 1, depending.According to PEMDAS, parentheses come first: 8 ÷ 2 (4)Then, even though multiplication is first in PEMDAS, you go left to right: 4 (4) = 16If you got 1, you’re in good company. That’s what I got at first too but most calculators I’ve tried get 16.I found this at Popular Mechanics and the debate continues online.

16 or 1, depending.

According to PEMDAS, parentheses come first: 8 ÷ 2 (4)

Then, even though multiplication is first in PEMDAS, you go left to right: 4 (4) = 16

If you got 1, you’re in good company. That’s what I got at first too but most calculators I’ve tried get 16.

I found this at Popular Mechanics and the debate continues online.

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Brothers And Sisters Of Leopold

If Leopold had one more sister he would have twice as many sisters as brothers.
If he had one more brother he would have the same number of each.

How many brothers and sisters does Leopold have?

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Three sisters and two brothers.

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Sum of Consecutives

What is the sum of the numbers in the following list which are consecutive?

15  5 10 28
24  7 18 26
11 21 17 13
22  9  1 20

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The consecutive numbers are: 9, 10, 11; 17, 18; and 20, 21, 22.

The sum of those numbers is 128.

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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

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Rows B and C, becoming:

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

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A Sign in Japan

This sign was seen in Japan. What does it mean?

A sign seen in Japan

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It’s a glass sign containing instructions on a glass door.
It says PULL on one side and PUSH on the opposite side.

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Counting Squares

How many squares of any size are in this grid?

4 x 4 grid

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30.There are:16 1×1 squares
9 2×2 squares
4 3×3 squares
1 4×4 square (the whole shape)Hence, 16 + 9 + 4 + 1 = 30.

30.

There are:

16 1×1 squares
9 2×2 squares
4 3×3 squares
1 4×4 square (the whole shape)

Hence, 16 + 9 + 4 + 1 = 30.

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Four Nines To Make a Hundred

How can you make four 9’s equal 100?

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99 9/9 = 100

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Betcha Find a Chocolate

Laura saw that there were three pieces of candy left in a bowl on the kitchen table. She knew they were either chocolates or caramels but didn’t know how many there were of each. What is the probability that there is a piece of chocolate candy in the bowl?

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7/8.The possible combinations are:
1. Chocolate Chocolate Chocolate
2. Caramel Caramel Caramel
3. Chocolate Chocolate Caramel
4. Caramel Caramel Chocolate
5. Chocolate Caramel Caramel
6. Caramel Chocolate Chocolate
7. Chocolate Caramel Chocolate
8. Caramel Chocolate CaramelNumber 2 is the only one that doesn’t have chocolate, thus Laura’s love of chocolate will more than likely be satiated.

7/8.

The possible combinations are:
1. Chocolate Chocolate Chocolate
2. Caramel Caramel Caramel
3. Chocolate Chocolate Caramel
4. Caramel Caramel Chocolate
5. Chocolate Caramel Caramel
6. Caramel Chocolate Chocolate
7. Chocolate Caramel Chocolate
8. Caramel Chocolate Caramel

Number 2 is the only one that doesn’t have chocolate, thus Laura’s love of chocolate will more than likely be satiated.

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The Average of Three

There are three numbers. The first two are 2/3 and 3/4.

What does the third number have to be to make the average of all three be 2?

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4 7/12In order for the average of three numbers to be 2, they must all add up to 6. That gives you this equation:
2/3 + 3/4 + n = 6Solve for n = 55/12, or 4 7/12.

4 7/12

In order for the average of three numbers to be 2, they must all add up to 6. That gives you this equation:
2/3 + 3/4 + n = 6

Solve for n = 55/12, or 4 7/12.

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