Riddles and Brain Teasers

91. To get the number in the fourth column, you add the numbers in column 1 and 2, then multiply by the number in column 2. f(n,m) = (n + m) * m
For example, f(2,3) = (2 + 3) * 3 = 15. Thus f(6,7) = (6 + 7) * 7 = 91

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Tagged with sequence

Who May Enter?

A green glass door admits only certain objects. Apples and balls are allowed, but pears and bats aren’t. What determines whether an item can enter?

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All words with a repeated letter are allowed. Green glass door, apple and ball.

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A Head, One Arm and Round Bottom

What has a head, one arm, one leg and a round bottom?

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A handicapped parking sign.

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Highest Product Using All Digits

What is the highest product that can be generated by multiplying two numbers while only using each digit once (1 through 9)?
For example, 12345678 * 9 = 111,111,102

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9642 * 87531 = 843,973,902

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What is the center of gravity?

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V. The letter ‘v’ is the center of the word gravity.

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Colored As A Maiden Tweaked

Colored as a maiden tweaked,
Time was naught when I began;
Through the garden I was sneaked,
I alone am the fall of man.

What am I?

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An apple.

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What Surrounds The World

What surrounds the world, yet dwells within a thimble?

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Space.

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Debbie’s Dragster

Debbie starts driving her dragster from rest and constantly accelerates to 60 mph in 10 seconds. How far does she travel in those 10 seconds?

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1/12 mileTen seconds is 1/6 of a minute and 1 minute is 1/60 of an hour, so 10 seconds is 1/360 of an hour.If you graph her trip with the speed on the y-axis and the time on the x-axis, you get a triangle with height of 60 mph and width of 1/360 of an hour. To calculate the area of the triangle, you multiply 1/2 × 1/360 × 60 = 1/12.

1/12 mile

Ten seconds is 1/6 of a minute and 1 minute is 1/60 of an hour, so 10 seconds is 1/360 of an hour.

If you graph her trip with the speed on the y-axis and the time on the x-axis, you get a triangle with height of 60 mph and width of 1/360 of an hour. To calculate the area of the triangle, you multiply 1/2 × 1/360 × 60 = 1/12.

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