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
Hawaiian Islands Riddle
Hint:
Ruins Town Riddle
Hint:
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
This Country Gave Us Books Riddle
And the cuddly Paddington Bear
Consulting detective Sherlock Holmes
And Robin Hood who kept things fair
Hint:
A Hard Spot To Get Out Of
Hint:
Many Things Can Be Played Riddle
If youre bored and have a set of these
There are many things that can be played
Each has a number, letter or head
And a diamond, club, heart or a spade
What is it?
There are many things that can be played
Each has a number, letter or head
And a diamond, club, heart or a spade
What is it?
Hint:
The Best Place For Ice Cream
Hint:
Hands That Don't Hold Riddle
Hands she has but does not hold, teeth she has but does not bite, feet she has but they are cold, eyes she has but without sight. Who is she?
Hint:
Neighbors With New Hampshire Riddle
I have the second lowest population of all US states. I am famous for my maple syrup. I am neighbors with New Hampshire. Which state am I?
Hint:
A Happy Nut Riddle
Hint:
Happy Man In Green Riddle
Hint:
The Hatred For Winter Riddle
Hint:
Meeting Computer Geeks Riddle
Hint:
Sheep Haircuts Riddle
Hint:
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