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).
Joe and Andrea want to copy three 60-minute cassette tapes. They have a 2-cassette recorder to copy the tapes, allowing them to copy two tapes at a time. Each side takes 30 minutes to be copied, so two tapes can be copied in an hour and the third will take another hour. Andrea bets Joe she can copy all three tapes in 90 minutes. Does she win the bet?
In the first 30 minutes Andrea copies the A sides of tape 1 and 2.
In the second 30 minutes, she copies tape 1 side B and tape 3 side A (finishing Tape 1).
In the last 30 minutes, she copies tape 2 side B and tape 3 side B.
Look in the mirror, then at the wall and back at the mirror to see what you saw. Use the saw to cut the table in half and join the two halves to make a whole. Put the “hole” on the wall and climb out.
I know, it’s lame. I like to have brain teasers that you can realistically guess, but this one’s so popular, I feel an obligation to include it.
My days are in the summer
When you’ll eat me when I’m hot
In fact I’ll even eat myself
Where battles tough are fought
But when you find me in a fight
‘Twill be high in the sky
And if you catch me napping
I suggest you let me lie
When you’re bad come to my house
From Ma get thoughts profound
Am I big or am I small?
Some say I’m just a pound.
