42 Brain Teasers – Complete List

42 Brain Teasers

Challenge your mind with these puzzling questions

#	Category	Difficulty	Question	Answer
1	Riddles	Easy	I speak without a mouth and hear without ears. I have no body, but I come alive with wind. What am I?	An echo
2	Riddles	Easy	The more you take, the more you leave behind. What am I?	Footsteps
3	Riddles	Medium	What has keys but no locks, space but no room, and you can enter but not go in?	A keyboard
4	Riddles	Medium	I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?	A map
5	Riddles	Medium	What can travel around the world while staying in a corner?	A stamp
6	Riddles	Easy	I am always hungry and will die if not fed, but whatever I touch will soon turn red. What am I?	Fire
7	Riddles	Hard	The person who makes it has no need of it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?	A coffin
8	Riddles	Easy	What gets wetter and wetter the more it dries?	A towel
9	Riddles	Medium	I have branches, but no fruit, trunk or leaves. What am I?	A bank
10	Riddles	Easy	What goes up but never comes down?	Your age
11	Riddles	Medium	What has a head, a tail, is brown, and has no legs?	A penny
12	Riddles	Medium	What belongs to you, but other people use it more than you?	Your name
13	Riddles	Medium	I’m light as a feather, but the strongest person can’t hold me for more than a few minutes. What am I?	Breath
14	Riddles	Easy	What can fill a room but takes up no space?	Light
15	Riddles	Easy	If you drop me, I’m sure to crack. Give me a smile, and I’ll always smile back. What am I?	A mirror
16	Logic	Hard	A farmer needs to take a fox, a chicken, and a sack of grain across a river. The boat is only large enough for the farmer and one item. If left alone, the fox will eat the chicken, and the chicken will eat the grain. How does the farmer get all three across the river safely?	1) Farmer takes chicken across. 2) Farmer returns alone. 3) Farmer takes fox across. 4) Farmer takes chicken back. 5) Farmer takes grain across. 6) Farmer returns alone. 7) Farmer takes chicken across.
17	Logic	Hard	You have two hourglasses, one that measures 7 minutes and one that measures 4 minutes. How can you measure exactly 9 minutes?	Start both hourglasses. When the 4-minute one empties, flip it. When the 7-minute one empties, flip it. When the 4-minute glass empties again, 8 minutes have passed. Flip the 7-minute glass one more time—it has 1 minute of sand left, which gives you 9 minutes total.
18	Logic	Hard	You have 12 balls that look identical, but one weighs slightly more or less than the others. You have a balance scale. In just three weighings, how can you identify the odd ball and determine if it’s heavier or lighter?	Divide the balls into 3 groups of 4. Weigh group 1 vs group 2. If equal, the odd ball is in group 3 – proceed with further strategic weighings. If unequal, the odd ball is in the heavier/lighter group. Continue with strategic divisions and comparisons to identify the specific ball.
19	Logic	Medium	A man builds a house with four walls. Each wall faces south. A bear walks by the house. What color is the bear?	White – the house is at the North Pole, so the bear must be a polar bear.
20	Logic	Medium	I have two coins that add up to 30 cents. One of them is not a nickel. What are the two coins?	A quarter and a nickel. (The clue says ONE of them is not a nickel, implying the other one is.)
21	Logic	Hard	Three people check into a hotel. They pay $30 to the manager and go to their room. The manager finds out that the room rate is $25 and gives $5 to the bellboy to return to the people. On the way to the room, the bellboy reasons that $5 would be difficult to share among three people, so he pockets $2 and gives $1 to each person. Now each person paid $10 and got back $1, so each paid $9, totaling $27. The bellboy has $2. Where is the remaining $1?	The question uses faulty logic. The correct accounting is: $25 (room) + $2 (bellboy) + $3 (returned to customers) = $30. There is no missing dollar.
22	Logic	Hard	You’re in a room with three light switches, each of which controls one of three light bulbs in the next room. You can flip the switches as many times as you want, but you can only enter the room with the light bulbs once. How do you determine which switch controls which bulb?	Turn on switch 1 for several minutes, then turn it off. Turn on switch 2 and enter the room. The bulb that is on is controlled by switch 2. The bulb that is off but warm is controlled by switch 1. The bulb that is off and cool is controlled by switch 3.
23	Logic	Hard	You have a 3-gallon jug and a 5-gallon jug. How can you measure exactly 4 gallons of water?	1) Fill the 5-gallon jug. 2) Pour from the 5-gallon jug to fill the 3-gallon jug, leaving 2 gallons in the 5-gallon jug. 3) Empty the 3-gallon jug. 4) Pour the 2 gallons from the 5-gallon jug into the 3-gallon jug. 5) Fill the 5-gallon jug again. 6) Pour from the 5-gallon jug to fill the 3-gallon jug, which already has 2 gallons, so you pour 1 gallon. 7) The 5-gallon jug now has 4 gallons left.
24	Logic	Medium	A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?	The doctor was the boy’s mother.
25	Logic	Easy	What can you hold in your right hand, but not in your left hand?	Your left hand
26	Wordplay	Medium	What five-letter word becomes shorter when you add two letters to it?	Short (becomes ‘shorter’)
27	Wordplay	Easy	What word in the English language is always spelled incorrectly?	Incorrectly
28	Wordplay	Medium	I am a word of six letters. Subtract one letter and twelve remains. What word am I?	Dozens
29	Wordplay	Hard	What word looks the same upside down and backwards?	SWIMS
30	Wordplay	Hard	What English word has three consecutive double letters?	Bookkeeper
31	Wordplay	Hard	What is the longest word in the English language with only one vowel?	Strengths
32	Wordplay	Hard	What common English word is nine letters long and each time you remove a letter from it, it still remains an English word – from nine letters right down to a single letter?	Startling → starting → staring → string → sting → sing → sin → in → I
33	Wordplay	Hard	What is the only word in the English language that ends with the letters ‘mt’?	Dreamt
34	Wordplay	Medium	Forward I am heavy, but backward I am not. What am I?	The word ‘ton’ (backward is ‘not’)
35	Wordplay	Medium	I am a six-letter word. My 1st to 3rd letters say what you do in bed, my 4th to 6th is what you have to do to make tea. What am I?	Layoff (Lay + off)
36	Math	Hard	Using only addition, how can you add eight 8’s to get the number 1000?	888 + 88 + 8 + 8 + 8 = 1000
37	Math	Hard	If 1 = 5, 2 = 25, 3 = 325, 4 = 4325, then 5 = ?	54325 (Each number is multiplied by 5 and then the previous number is added to the beginning)
38	Math	Medium	If 2 = 6, 3 = 12, 4 = 20, 5 = 30, then 6 = ?	42 (The pattern is n × (n+1))
39	Math	Medium	A bat and a ball cost $1.10 in total. The bat costs $1.00 more than the ball. How much does the ball cost?	5 cents (If the ball costs x, then the bat costs x + $1.00, and x + (x + $1.00) = $1.10, so 2x + $1.00 = $1.10, thus x = 5 cents)
40	Math	Easy	If you multiply me by any other number, the answer will always be the same. What number am I?	Zero
41	Math	Medium	I am an odd number. Take away one letter and I become even. What number am I?	Seven (take away the ‘s’ and it becomes ‘even’)
42	Math	Hard	If a hen and a half lays an egg and a half in a day and a half, how many eggs will half a dozen hens lay in half a dozen days?	24 eggs (If 1.5 hens lay 1.5 eggs in 1.5 days, then 1 hen lays 1 egg in 1.5 days. So 1 hen lays 2/3 egg per day. Thus 6 hens lay 4 eggs per day, and in 6 days they