A Rickety Bridge Riddle
Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?
Hint:
17 mins.
The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.
Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.
1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)
Total time = 2 + 2 + 10 + 1 + 2 = 17 mins Did you answer this riddle correctly?
YES NO
The initial solution most people will think of is to use the fastest person as an usher to guide everyone across. How long would that take? 10 + 1 + 7 + 1 + 2 = 21 mins. Is that it? No. That would make this question too simple even as a warm up question.
Let's brainstorm a little further. To reduce the amount of time, we should find a way for 10 and 7 to go together. If they cross together, then we need one of them to come back to get the others. That would not be ideal. How do we get around that? Maybe we can have 1 waiting on the other side to bring the torch back. Ahaa, we are getting closer. The fastest way to get 1 across and be back is to use 2 to usher 1 across. So let's put all this together.
1 and 2 go cross
2 comes back
7 and 10 go across
1 comes back
1 and 2 go across (done)
Total time = 2 + 2 + 10 + 1 + 2 = 17 mins Did you answer this riddle correctly?
YES NO
I Get Stronger Riddle
I can help you have some fun,
Sometimes I get stronger from the sun,
If you never give me a break,
You will find I never wake,
I am optimistic on one side,
I can be short, fat, tall or wide,
Rectangle and cylinder are two of my shapes,
And I can even help you make video tapes,
Sometimes you must wait for me to get ready,
Just hold on for a few hours and be steady,
I can help you get around the mall,
Or help you make a telephone call.
What am I?
Sometimes I get stronger from the sun,
If you never give me a break,
You will find I never wake,
I am optimistic on one side,
I can be short, fat, tall or wide,
Rectangle and cylinder are two of my shapes,
And I can even help you make video tapes,
Sometimes you must wait for me to get ready,
Just hold on for a few hours and be steady,
I can help you get around the mall,
Or help you make a telephone call.
What am I?
Hint:
Written In Blood Riddle
On a dark, stormy Halloween night, four kids named Luke, John, Sarah and Bob walk into a haunted house during a blackout. Only one can escape. They take a staircase to the second floor, a trapdoor on the left, then go up the ladder to the right, followed by a 28-foot slide to the basement through the mouth of a Giant Panda. In one corner of the murky cellar is a chainsaw, a dagger, a rope with a noose and an electric chair. Written on the wall in blood are the words, Only one will survive choose your death! Bob takes the rope, Sarah picks up the dagger, John chooses the chainsaw and Luke uses the chair.
Who survives?
Who survives?
Hint:
A Hard Spot To Get Out Of
Hint:
The Card Trick Riddle
A couple had to take shelter in a hotel for they could not proceed their journey in the rain. Having nothing to do at all, they started playing cards. Suddenly there was a short circuit and the lights went off. The husband inverted the position of 15 cards in the deck (52 cards normal deck) and shuffled the deck.
Now he asked his wife to divide the deck into two different piles which may not be equal but both of them should have equal number of cards facing up. There was no source of light in the room and the wife was unable to see the cards.
For a certain amount of time, she thought and then divided the cards in two piles. To the husbands astonishment, both of the piles had equal number of cards facing up.
How did she do it?
Now he asked his wife to divide the deck into two different piles which may not be equal but both of them should have equal number of cards facing up. There was no source of light in the room and the wife was unable to see the cards.
For a certain amount of time, she thought and then divided the cards in two piles. To the husbands astonishment, both of the piles had equal number of cards facing up.
How did she do it?
Hint:
The answer is very simple. All she had to do is take the fifteen cards from the top and reverse them. This would make another pile out of that and there will be two piles - one of 15 cards and one of 37 cards. Also both of them will have the same number of inverted cards.
Just think about it and if the mathematical explanation will help you understand better, here it is.
Assume that there were p inverted cards initially in the top 15 cards. Then the remaining 37 cards will hold 15-p inverted cards.
Now when she reverses the 15 cards on the top, the number of inverted cards will become 15-p and thus the number of inverted cards in both of the piles will become same. Did you answer this riddle correctly?
YES NO
Just think about it and if the mathematical explanation will help you understand better, here it is.
Assume that there were p inverted cards initially in the top 15 cards. Then the remaining 37 cards will hold 15-p inverted cards.
Now when she reverses the 15 cards on the top, the number of inverted cards will become 15-p and thus the number of inverted cards in both of the piles will become same. Did you answer this riddle correctly?
YES NO
A Sound Economic Reason
You will know that I am coming from the jingle of my bell, but exactly who I am is not an easy thing to tell. Children, they adore me for they find me jolly, but I do not see them when the halls are decked with holly.
My job often leaves me frozen, I am a man that all should know, but I do not do business in times of sleet or ice or snow. I travel much on business, but no reindeer haul me around, I do all my traveling firmly on the ground.
I love the time of Christmas, but that's not my vocational season, and I assure that is because of a sound economic reason.
Who am I?
My job often leaves me frozen, I am a man that all should know, but I do not do business in times of sleet or ice or snow. I travel much on business, but no reindeer haul me around, I do all my traveling firmly on the ground.
I love the time of Christmas, but that's not my vocational season, and I assure that is because of a sound economic reason.
Who am I?
Hint:
Living In The Lighthouse
Every morning a man wakes up, turns off the light, eats breakfast, and leaves for work. In the early evening he comes home and turns on the light. One night he forgot to turn on the light. The next morning he died shortly after waking up. Why did he die?
Hint:
He lived in a lighthouse. When he woke up he looked out the window. To his horror he saw a shipwreck, which was his fault for leaving the light off. He killed himself out of guilt. Did you answer this riddle correctly?
YES NO
YES NO
Under An Umbrella Riddle
Hint:
Seen Up In The Sky
This can be seen up in the sky
But it is not a kite
It is a giant ball of gas
Which gives you heat and light.
What am I?
But it is not a kite
It is a giant ball of gas
Which gives you heat and light.
What am I?
Hint:
Counting In Binary Riddle
Hint:
Grown And Bought Riddle
I can be grown, and I can be bought.
I can be painted, or left bare.
I can be round, or square.
What am I?
Hint:
An Icy Treat You Know
You will know that I am coming from the jingle of my bell, but exactly who I am is not an easy thing to tell. Children, they adore me for they find me jolly, but I do not see them when the halls are decked with holly.
My job often leaves me frozen, I am a man that all should know, but I do not do business in times of sleet or ice or snow. But I have a cold and icy treat you definitely know. I travel much on business, but no reindeer haul me around, I do all my traveling firmly on the ground.
I love the time of Christmas, but that's not my vocational season, and I assure that is because of a sound economic reason.
Who am I?
My job often leaves me frozen, I am a man that all should know, but I do not do business in times of sleet or ice or snow. But I have a cold and icy treat you definitely know. I travel much on business, but no reindeer haul me around, I do all my traveling firmly on the ground.
I love the time of Christmas, but that's not my vocational season, and I assure that is because of a sound economic reason.
Who am I?
Hint:
Seeing In The Dark Riddle
I get shorter the more Im used but Im not a pencil
Im made of wax but Im not a crayon
I can help you see in the dark but Im not a flashlight
Im often found on a birthday cake but Im not icing
What am I?
Im made of wax but Im not a crayon
I can help you see in the dark but Im not a flashlight
Im often found on a birthday cake but Im not icing
What am I?
Hint:
Tall When Young Riddle
Hint:
Little Miss Eticote Riddle
Little Miss Eticote
In her white petticoat
And her red nose
The longer she stands
The shorter she grows
In her white petticoat
And her red nose
The longer she stands
The shorter she grows
Hint:
Add Your Riddle Here
Have some tricky riddles of your own? Leave them below for our users to try and solve.