Mind Twisters
If you pass the person in 2nd place in a race, what place are you in?
2nd place
What is the only even prime number?
2
A pizza is cut into 8 slices. You eat 3. What fraction is left?
5/8
Solve 2x + 5 = 15
x = 5
Two fathers and two sons go fishing. They catch 3 fish. Each gets one whole fish. How?
Grandfather, father, son
A farmer has 17 sheep. All but 9 die. How many are left?
9
What is the only number that has the same number of letters as its values?
4
A train leaves at 3:00 travelling at 60km/h. Another train leaves at 4:00 at 90km/h. When will the faster train catch up?
6:00
Convert π/6 radians into degrees.
30o
You need exactly 4 liters of water, but only have 3L and 5L jugs. How do you do it?
Fill 5L; pour into 3L; empty 3L; pour remaining 2L into 3L; fill 5L again; pour until 3L is full; exactly 4L left.
You see a boat filled with people, but there isn't a single person on board. How?
They're all married.
Which number is both a square and a cube?
64
A shop discounts a $50 shirt by 20%. Then gives an extra 10% off the reduced price. What's the final price?
$36
Expand (x + 2)(x - 3)
x2 - x - 6
What occurs once in every minute, twice in every moment, but never in a thousand years?
The letter "m"
A man look at a picture and says: "Brothers and sisters I have none, but that man's father is my father's son." Who is in the picture?
His son
If you write down all the numbers from 1 to 100, how many times does the digit "7" appear?
20
A farmer must cross a river with a wolf, a goat, and a cabbage. He can take one at a time. The wolf can't be left alone with the goat, the goat can't be left with the cabbage. How does he do it?
Goat first, then wolf, bring goat back, take cabbage, return for goat.
A bag has 4 red and 6 blue marbles. Two are drawn without replacement. What's the probability both are red?
2/15
You are in a dark room with one match, a candle, a lantern, and a fireplace. Which do you light first?
The match
I have a large money box, 50 cm wide and 25 cm tall. Roughly how may coins can I place until my money box is no longer empty?
1
What is the largest number between one and a million without the letter "n"?
88
Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a car; behind the others, goats. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 3, which has a goat. He then says to you, "Do you want to pick door No. 2?" Is it to your advantage to switch your choice?
Yes
A die is rolled twice. Find the probability of 7?
1/6
You have 3 switches in one room and 3 light bulbs in another (you can't see the bulbs from the switches). You can only go into the bulb room once. How can you figure out which switch controls which bulb?
Turn on the first switch for a while, then turn it off. Turn on the second switch and leave it on. Enter the bulb room: the bulb that’s lit = switch 2, the warm but off bulb = switch 1, the cold bulb = switch 3.)