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
Four Days Of School Riddle
A student has missed an excessive number of days at school and thus the principal called him to his office and requested for an explanation.
The student said, There just isnt enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, thats 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days.
Add all of that up and you get about 361 days. That only leaves 4 days for school.
The principal is confused, but cant figure out why. What is wrong with the students argument?
The student said, There just isnt enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, thats 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days.
Add all of that up and you get about 361 days. That only leaves 4 days for school.
The principal is confused, but cant figure out why. What is wrong with the students argument?
Hint:
The student is double counting a lot of the days. A lot of the time spent sleeping, eating, and relaxing occurs during weekends and the summer. Weekends also occur during the summer, so all of these hours are getting counted several times.
And, school is not an all day affair. So the 4 days actually represents more days of school. If school is 6 hours per day, those four days represents 16 days of school. Did you answer this riddle correctly?
YES NO
And, school is not an all day affair. So the 4 days actually represents more days of school. If school is 6 hours per day, those four days represents 16 days of school. Did you answer this riddle correctly?
YES NO
Cakes For Grandma Riddle
You are on your way to visit your Grandma, who lives at the end of the valley. It's her birthday, and you want to give her the cakes you've made.
Between your house and her house, you have to cross 7 bridges, and as it goes in the land of make believe, there is a troll under every bridge! Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake.
How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?
Between your house and her house, you have to cross 7 bridges, and as it goes in the land of make believe, there is a troll under every bridge! Each troll, quite rightly, insists that you pay a troll toll. Before you can cross their bridge, you have to give them half of the cakes you are carrying, but as they are kind trolls, they each give you back a single cake.
How many cakes do you have to leave home with to make sure that you arrive at Grandma's with exactly 2 cakes?
Hint:
2: At each bridge you are required to give half of your cakes, and you receive one back. Which leaves you with 2 cakes after every bridge. Did you answer this riddle correctly?
YES NO
YES NO
The Robbery On The Third Floor Riddle
My wife and I took a much-needed holiday in England. It's a long flight from New York to London. We checked into a nice hotel. After a long day of sightseeing we just collapsed into bed. Just a few minutes ago, we were woken up by some noises outside. I looked out the window and the police were everywhere. They yelled up to me that there was a robbery and a murderer on the second floor. I'm on the third floor, and I can see and I can see that the cops have the stairs and elevators locked down. The murderer can't get up to our floor, so we're in no danger. My wife and I are tired, so we're going back to bed. I really hope they catch the guy.
Why did the police yell to the guy if he was on the 3rd floor?
Why did the police yell to the guy if he was on the 3rd floor?
Hint:
America and England have different ways of numbering floors. In America, it goes 1st floor, 2nd floor, 3rd floor. In England, it goes ground floor, 1st floor, 2nd floor. Did you answer this riddle correctly?
YES NO
YES NO
Providing Light Riddle
I provide light but I'm not a candle
I'm hot but Im not a bonfire
I have rays but Im not an aquarium
I'm a star but Im not a celebrity
I rise in the morning but I'm not someone getting out of bed
What am I?
I'm hot but Im not a bonfire
I have rays but Im not an aquarium
I'm a star but Im not a celebrity
I rise in the morning but I'm not someone getting out of bed
What am I?
Hint:
Superman's Beef Broth Riddle
Hint:
Carrying Children Riddle
Hint:
The Number Pattern Riddle
Hint:
31131211131221.
Each line, excluding the first, describes the one before it.
1
11 <---describes 1st line, read as "one 1"
21 <---describes 2nd line, read as "two 1's"
1211 <---describes 3rd line, read as "one 2 two 1's" Did you answer this riddle correctly?
YES NO
Each line, excluding the first, describes the one before it.
1
11 <---describes 1st line, read as "one 1"
21 <---describes 2nd line, read as "two 1's"
1211 <---describes 3rd line, read as "one 2 two 1's" Did you answer this riddle correctly?
YES NO
The Daily Ride Riddle
You ride on me every day but barely notice,
Im hot and cold at the very same time,
Im the densest of my clan,
And my first three help you enjoy music.
What am I?
Im hot and cold at the very same time,
Im the densest of my clan,
And my first three help you enjoy music.
What am I?
Hint:
Earth. Most people dont stop to think that theyre hurtling through space on a huge planet. At any given time the Earth has burning hot magma and freezing arctics at the same time. The Earth is the densest planet and the first three letters, ear help you listen to music. Did you answer this riddle correctly?
YES NO
YES NO
This Does Reflect Riddle
Careful because I may break in two
It would be correct to say this does reflect
Breaking me incurs a seven year hex!
What am I?
Hint:
Always Tells The Truth Riddle
Hint:
Open Me Up Riddle
Hint:
Baseball And Piano Riddle
Hint:
Counting Time Riddle
Hint:
Middle Ages Riddle
Hint:
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