10 Boxes Riddle
There are ten boxes containing some balls. Each of the ball weighs exactly 10 grams. One of those boxes have defective balls (all the defective balls weigh 9 grams each).
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
Hint:
Let us simplify boxes by naming them from 1 to 10.
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
BDay Bash Riddle
I engaged in a strange activity. My birthday was approaching and I decided to collect money for my birthday bash. On the first day of the month, I kept a dollar in my piggy bank, on the second, I kept two dollars and on the third, I kept three and so on.
On my birthday, I had a total of 276 dollars in my piggy bank. Can you find out on which day of the month was my birthday?
On my birthday, I had a total of 276 dollars in my piggy bank. Can you find out on which day of the month was my birthday?
Hint:
23rd.
The easiest way to find out without engaging in any formula would be to simply add them:
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 = 276 Did you answer this riddle correctly?
YES NO
The easiest way to find out without engaging in any formula would be to simply add them:
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 = 276 Did you answer this riddle correctly?
YES NO
Afternoon Bike Ride Riddle
Hester goes out for an afternoon bicycle ride. She rides for one hour at five miles an hour, then three hours at four miles an hour and finally two hours at seven miles an hour. How many miles did she ride in total?
Hint:
31 miles.
1 hour at 5 mph = 5 miles
3 hours at 4 mph = 12 miles
2 hours at 7 mph = 14 miles
5 + 12 + 14 = 31 miles Did you answer this riddle correctly?
YES NO
1 hour at 5 mph = 5 miles
3 hours at 4 mph = 12 miles
2 hours at 7 mph = 14 miles
5 + 12 + 14 = 31 miles Did you answer this riddle correctly?
YES NO
A Place With Nothing There Riddle
I have towns but no houses
Rivers but no water
Forests but no trees
And mountains but no rocks.
What am I?
Rivers but no water
Forests but no trees
And mountains but no rocks.
What am I?
Hint: I show you where they are.
Ghost At The Gym Riddle
Hint:
Square Rings Riddle
Hint:
Rides At The Fair Riddle
Hint:
Unexpected Visitors Riddle
Its 3am, the doorbell rings and you wake up. Unexpected visitors! Its your parents and they are here for breakfast. You have strawberry jam, honey, wine, bread and cheese. What is the first thing you open?
Hint:
5 Little Items Riddle
Hint:
The German Spy Riddle
A German spy was in Canada trying to steal insider information on how to set up new Maple Syrup factories in Germany. He was being introduced to the operations manager of the biggest factory in Canada.
However the manager was suspicious and decided to test him with a question before he trusted him. So he asked, what would you be sure to find in the middle of Toronto?
The spy thought fast and came up with an answer for the manager.
What did he say?
However the manager was suspicious and decided to test him with a question before he trusted him. So he asked, what would you be sure to find in the middle of Toronto?
The spy thought fast and came up with an answer for the manager.
What did he say?
Hint:
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
Bad Kids Riddle
Hint:
Less Than 100 Riddle
Find a number less than 100 that is increased by one-fifth of its value when its digits are reversed.
Hint:
Accused Of Confusion Riddle
I make you frown and scratch your head, to find my solution will leave you mumbling. Many love me, many hate me and my nature's humbling. Fabled creatures sometimes use me, of confusion some accuse me. What am I?
Hint:
Prohibited Chess Riddle
Hint:
Add Your Riddle Here
Have some tricky riddles of your own? Leave them below for our users to try and solve.